An anti-air craft gun can take a maximum of four shots at an enemy plane moving away from it. The probability of hitting the plane at the first, second, third and fourth shots are 0.4, 0.3, 0.2 and 0.1 respectively. What is the probability that the plane is hit when all the four shots are fired? a) 0.6872 b) 0.4379 c) 0.6976 d) 0.3452

An anti-air craft gun can take a maximum of four shots at an enemy plane moving away from it. The probability of hitting the plane at the first, second, third and fourth shots are 0.4, 0.3, 0.2 and 0.1 respectively. What is the probability that the plane is hit when all the four shots are fired? a) 0.6872 b) 0.4379 c) 0.6976 d) 0.3452
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Answer :

c) 0.6976
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Related questions

An anti-aircraft gun can take a maximum of four shots at any plane moving away from it. The probabilities of hitting the plane at 1st, 2nd, 3rd -Maths 9th

Description : An anti-aircraft gun can take a maximum of four shots at any plane moving away from it. The probabilities of hitting the plane at 1st, 2nd, 3rd -Maths 9th

Last Answer : (c) 0.6976Let A, B, C, D be the events that 1st, 2nd, 3rd and 4th shots hits the plane respectively. Then, P(A) = 0.4, P(B) = 0.3, P(C) = 0.2, P(D) = 0.1 ⇒ P(not A) = 1 - P(A),= ... and D are independent events) P(At least one shot hits the plane) = 1 - P(None hits the plane) = 1 - 0.3024 = 0.6976

A man can hit a target once in 4shots. If he fires 4 shots in succession, what is the probability that he will hit his target? a) 175/256 b) 81/256 c) 1/256 d) 1/256

Description : A man can hit a target once in 4shots. If he fires 4 shots in succession, what is the probability that he will hit his target? a) 175/256 b) 81/256 c) 1/256 d) 1/256

Last Answer : a) 175/256

When two dice are rolled, find the probability of getting a greater number on the first die than the one on the second, given that the sum should equal 8. a) 5/18 b) 1/18 c) 2/5 d) 1/5

Description : When two dice are rolled, find the probability of getting a greater number on the first die than the one on the second, given that the sum should equal 8. a) 5/18 b) 1/18 c) 2/5 d) 1/5

Last Answer : c) 2/5

There are 6 positive numbers and 8 negative numbers. Four numbers are chosen at random and multiplied. The probability that the product is a positive number is: a) 502/1001 b) 505/1001 c) 501/1001 d) 503/1001

Description : There are 6 positive numbers and 8 negative numbers. Four numbers are chosen at random and multiplied. The probability that the product is a positive number is: a) 502/1001 b) 505/1001 c) 501/1001 d) 503/1001

Last Answer : b) 505/1001

Two cards are drawn at random from a pack of 52 cards. What is the probability that both of them are either black or queen cards? a) 55/442 b) 54/221 c) 55/221 d) 51/221

Description : Two cards are drawn at random from a pack of 52 cards. What is the probability that both of them are either black or queen cards? a) 55/442 b) 54/221 c) 55/221 d) 51/221

Last Answer : c) 55/221

What is the probability that a two digit number selected at random will be a multiple of '3' and not a multiple of '7'? e) 13/45 f) 14/45 g) 23/90 h) 19/45

Description : What is the probability that a two digit number selected at random will be a multiple of '3' and not a multiple of '7'? e) 13/45 f) 14/45 g) 23/90 h) 19/45

Last Answer : Answer: a

The probability that an egg does not hatch is 1/3. What is the probability that 3 out of 4 eggs hatch? a) 8/81 b) 23/81 c) 32/81 d) 8/9

Description : The probability that an egg does not hatch is 1/3. What is the probability that 3 out of 4 eggs hatch? a) 8/81 b) 23/81 c) 32/81 d) 8/9

Last Answer : c) 32/81

A pack contains 4 blue, 2 red and 3 black pens. If a pen is drawn at random from the pack, replaced and the process repeated 2 more times, what is the probability of drawing 2 blue pens and 1 black pen? a) 16/243 b) 16/283 c) 14/243 d) 23/729

Description : A pack contains 4 blue, 2 red and 3 black pens. If a pen is drawn at random from the pack, replaced and the process repeated 2 more times, what is the probability of drawing 2 blue pens and 1 black pen? a) 16/243 b) 16/283 c) 14/243 d) 23/729

Last Answer : a) 16/243

Four equal sized maximum circular plates are cut off from a square sheet of area 784 cm2. What is the circumference of each plate? a) 22 cm b) 44 cm c) 42 cm d) 40cm

Description : Four equal sized maximum circular plates are cut off from a square sheet of area 784 cm2. What is the circumference of each plate? a) 22 cm b) 44 cm c) 42 cm d) 40cm

Last Answer : b) 44 cm

The external length, breadth and height of a closed box are 10cm, 9cm and 7cm respectively. The total inner surface area of the box is 262 sq.cm. If the walls of the box are of uniform thickness “t” cm, then “t” equals a) 1cm b) 23/3 cm c) 28/9 cm d) 42.5 cm

Description : The external length, breadth and height of a closed box are 10cm, 9cm and 7cm respectively. The total inner surface area of the box is 262 sq.cm. If the walls of the box are of uniform thickness “t” cm, then “t” equals a) 1cm b) 23/3 cm c) 28/9 cm d) 42.5 cm

Last Answer : a) 1cm

On Ashok marg, three consecutive traffic lights change after 36, 42 and 72 seconds respectively. If the lights are switched on at 9.00 A.M sharp, at what time will they change simultaneously? a) 9 :08 :44 b) 9:08:24 c) 9:08:04 d) 9:08:34

Description : On Ashok marg, three consecutive traffic lights change after 36, 42 and 72 seconds respectively. If the lights are switched on at 9.00 A.M sharp, at what time will they change simultaneously? a) 9 :08 :44 b) 9:08:24 c) 9:08:04 d) 9:08:34

Last Answer : b) 9:08:24

Two pipes can fill a tank in 20 and 24 minutes respectively and another pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank in gallons is: a)100 b)110 c)120 d)140

Description : Two pipes can fill a tank in 20 and 24 minutes respectively and another pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank in gallons is: a)100 b)110 c)120 d)140

Last Answer : c)120

I forgot the last digit of a 7-digit telephone number. If I randomly dial the final 3 digits after correctly dialing the first four, then what is the chance of dialing the correct number? a) 1/1001 b) 1/1000 c) 1/999 d) 1/990

Description : I forgot the last digit of a 7-digit telephone number. If I randomly dial the final 3 digits after correctly dialing the first four, then what is the chance of dialing the correct number? a) 1/1001 b) 1/1000 c) 1/999 d) 1/990

Last Answer : b) 1/1000

From a total of six men and four ladies, a committee of three is to be formed. If Mrs.X is not willing to join the committee in which Mr.Y is a member, whereas Mr.Y is willing to join the committee only if Mrs.Z is included. How many such committees are possible? a) 138 b) 128 c) 112 d) 91

Description : From a total of six men and four ladies, a committee of three is to be formed. If Mrs.X is not willing to join the committee in which Mr.Y is a member, whereas Mr.Y is willing to join the committee only if Mrs.Z is included. How many such committees are possible? a) 138 b) 128 c) 112 d) 91

Last Answer : d) 91

The maximum number of boys among which 1001 balls and 910 bats can be distributed in such a way that each boy gets the same number of balls and bats is a) 91 b) 910 c) 1001 d) 1911

Description : The maximum number of boys among which 1001 balls and 910 bats can be distributed in such a way that each boy gets the same number of balls and bats is a) 91 b) 910 c) 1001 d) 1911

Last Answer : a) 91

Which one of the following numbers can be removed from the set S= {0,2,4,5,9}, without changing the average of the set? a) 0 b) 2 c) 4 d) 5

Description : Which one of the following numbers can be removed from the set S= {0,2,4,5,9}, without changing the average of the set? a) 0 b) 2 c) 4 d) 5

Last Answer : c) 4

Two trains 240m and 170m in length are running towards each other on parallel tracks. One train has a speed of 51kmph and the other has a speed of 45kmph. In what time after the meet first will they be clear of each other? a) 6.714s b) 12.2 s c) 15.375s d) 16s

Description : Two trains 240m and 170m in length are running towards each other on parallel tracks. One train has a speed of 51kmph and the other has a speed of 45kmph. In what time after the meet first will they be clear of each other? a) 6.714s b) 12.2 s c) 15.375s d) 16s

Last Answer : c) 15.375s

79.93 × 35.02 -59.93 × 85.08 + 74.98 × 44.04 =? a) 1420 b) 1000 c) 1580 d) 870 e) 1260

Description : 79.93 × 35.02 -59.93 × 85.08 + 74.98 × 44.04 =? a) 1420 b) 1000 c) 1580 d) 870 e) 1260

Last Answer : ? ≈ 80 × 35-60 × 85 + 75 × 44 =2800 – 5100 + 3300 = 1000 Answer: b)

119 + 784 ÷ 32 x 116 = ? a) 2961 b) 3121 c) 2564 d) 2861 e) 2941

Description : 119 + 784 ÷ 32 x 116 = ? a) 2961 b) 3121 c) 2564 d) 2861 e) 2941

Last Answer : 119 + 784 ÷ 32 x 116 = ? Sol: 119 + 24.5 x 116 =? 119 + 2842 = ? ? = 2961 Answer: a)

119 + 784 ÷ 32 x 116 = ? a) 2961 b) 3121 c) 2564 d) 2861 e) 2941

Description : 119 + 784 ÷ 32 x 116 = ? a) 2961 b) 3121 c) 2564 d) 2861 e) 2941

Last Answer : 119 + 784 ÷ 32 x 116 = ? Sol: 119 + 24.5 x 116 =? 119 + 2842 = ? ? = 2961 Answer: a)

When a number is divided by 36, it leaves a remainder of 19. What will be the remainder when the same number is divided by 12? a) 17 b) 7 c) 34 d) 19

Description : When a number is divided by 36, it leaves a remainder of 19. What will be the remainder when the same number is divided by 12? a) 17 b) 7 c) 34 d) 19

Last Answer : b) 7

How many numbers greater than 400 can be formed with digits 3,4,8,9 with no digits being repeated? a) 24 b) 18 c) 42 d) 45

Description : How many numbers greater than 400 can be formed with digits 3,4,8,9 with no digits being repeated? a) 24 b) 18 c) 42 d) 45

Last Answer : c) 42

Find the sum of divisors of 544 which are perfect squares. a) 32 b) 64 c) 68 d) 21

Description : Find the sum of divisors of 544 which are perfect squares. a) 32 b) 64 c) 68 d) 21

Last Answer : d) 21

A building which is 64 meters high casts a shadow of length 96 meters. The height of a telephone tower which casts a shadow of 180 meters under similar conditions will be a) 100m b) 120m c) 180m d) 96m

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Last Answer : b) 120m

What is the highest power of 3 in 165!? a) 80 b) 81 c) 79 d) 73

Description : What is the highest power of 3 in 165!? a) 80 b) 81 c) 79 d) 73

Last Answer : b) 81

A can do a work in 15 days and B in 20 days. If they work together for 4 days, then the fraction of work that is left is a) 7/15 b) 8/10 c) 8/15 d) 7/20

Description : A can do a work in 15 days and B in 20 days. If they work together for 4 days, then the fraction of work that is left is a) 7/15 b) 8/10 c) 8/15 d) 7/20

Last Answer : c) 8/15

Twenty workers can complete a piece of work in 30 days. After how many days should 5 workers leave the job so that the work is completed in 35 days? a) 5 days b) 10 days c) 15 days d) 20 days

Description : Twenty workers can complete a piece of work in 30 days. After how many days should 5 workers leave the job so that the work is completed in 35 days? a) 5 days b) 10 days c) 15 days d) 20 days

Last Answer : c) 15 days

Two trains are running in opposite direction with the same speed. If the length of each train is 135 meters and they cross each other in 18 seconds, the speed of each train is a) 29km/hr b) 35km/hr c) 27km/hr d) 28km/hr

Description : Two trains are running in opposite direction with the same speed. If the length of each train is 135 meters and they cross each other in 18 seconds, the speed of each train is a) 29km/hr b) 35km/hr c) 27km/hr d) 28km/hr

Last Answer : c) 27km/hr

A trader mixes Ariel detergent costing Rs. 64 per kg with “Surf excel” which costs Rs. 76per kg in the ratio 1:3. If the cost of Surf excel drops to Rs.74 per kg, then in what ratio should he mix the two to leave the cost of mixture unchanged? a) 1:9 b) 1:8 c) 9:1 d) 8:1

Description : A trader mixes Ariel detergent costing Rs. 64 per kg with “Surf excel” which costs Rs. 76per kg in the ratio 1:3. If the cost of Surf excel drops to Rs.74 per kg, then in what ratio should he mix the two to leave the cost of mixture unchanged? a) 1:9 b) 1:8 c) 9:1 d) 8:1

Last Answer : a) 1:9

I bought 15 pens and sold 12 of them at the cost price of 18 pens. What is the profit percentage? a) 50 b) 25 c) 30 d) 45

Description : I bought 15 pens and sold 12 of them at the cost price of 18 pens. What is the profit percentage? a) 50 b) 25 c) 30 d) 45

Last Answer : a) 50

There are three events A, B and C , one of which must and only can happen. If the odds are 8:3 against A, 5:2 against B, then the odds against C must be: e) 13:7 f) 3:2 g) 43:77 h) 43:34

Description : There are three events A, B and C , one of which must and only can happen. If the odds are 8:3 against A, 5:2 against B, then the odds against C must be: e) 13:7 f) 3:2 g) 43:77 h) 43:34

Last Answer : Answer : d

A flag staff 17.5 m high casts a shadow of length 40.25m. What will be the height of a building, which casts a shadow of length 28.75m under similar conditions? a) 14m b) 11.4m c) 13.5m d) 12.5 m

Description : A flag staff 17.5 m high casts a shadow of length 40.25m. What will be the height of a building, which casts a shadow of length 28.75m under similar conditions? a) 14m b) 11.4m c) 13.5m d) 12.5 m

Last Answer : d) 12.5 m

What is the greatest 6-digit number that is divisible by 15, 24 and 28? a) 999650 b)999600 c)999825 d)999570

Description : What is the greatest 6-digit number that is divisible by 15, 24 and 28? a) 999650 b)999600 c)999825 d)999570

Last Answer : b)999600

A committee is to be formed comprising 7 members such that there is a simple majority of men and at-least 1 woman. The shortlist consists of 9 men and 6 women. In how many ways can this committee be formed? a) 3724 b) 4914 c) 3928 d) 4913

Description : A committee is to be formed comprising 7 members such that there is a simple majority of men and at-least 1 woman. The shortlist consists of 9 men and 6 women. In how many ways can this committee be formed? a) 3724 b) 4914 c) 3928 d) 4913

Last Answer : b) 4914

Fresh grapes contain 70% of water while dry grapes contain 30% of water. Find the weight of dry grapes which contain the same quantity of water as 30kg of fresh grapes? a) 30kg b) 40kg c) 70kg d) 80 kg

Description : Fresh grapes contain 70% of water while dry grapes contain 30% of water. Find the weight of dry grapes which contain the same quantity of water as 30kg of fresh grapes? a) 30kg b) 40kg c) 70kg d) 80 kg

Last Answer : c) 70kg

In how many ways can the letters of the word EDUCATION be rearranged such that the relative positions of the vowels and the consonants remain the same as in the word EDUCATION? a) 9!/4 b) 4!*5! c) 4!*5 d) 9!-4!

Description : In how many ways can the letters of the word EDUCATION be rearranged such that the relative positions of the vowels and the consonants remain the same as in the word EDUCATION? a) 9!/4 b) 4!*5! c) 4!*5 d) 9!-4!

Last Answer : b) 4!*5!

25 buses are running between two places P and Q. In how many ways can a person go from P to Q and return by a different bus? a) 300 b) 625 c) 600 d) 650

Description : 25 buses are running between two places P and Q. In how many ways can a person go from P to Q and return by a different bus? a) 300 b) 625 c) 600 d) 650

Last Answer : c) 600

If a clock strikes once at 1’o clock, twice at 2’o clock and twelve times at 12’o clock and again once at 1’o clock and so on, how many times will the clock strike in the course of 2 days? a) 156 b) 312 c) 78 d) 288

Description : If a clock strikes once at 1’o clock, twice at 2’o clock and twelve times at 12’o clock and again once at 1’o clock and so on, how many times will the clock strike in the course of 2 days? a) 156 b) 312 c) 78 d) 288

Last Answer : b) 312

A cylindrical drum of 15cm radius and 70cm height is full of water. The water is emptied into a rectangular tank 225cm long and 70cm wide. Find the height of water level in the tank. a) 3.5cm b) 2.25cm c) 3.142cm d) 1.57cm

Description : A cylindrical drum of 15cm radius and 70cm height is full of water. The water is emptied into a rectangular tank 225cm long and 70cm wide. Find the height of water level in the tank. a) 3.5cm b) 2.25cm c) 3.142cm d) 1.57cm

Last Answer : c) 3.142cm

The cost of preparing a cricket ground of rectangular shape at 70 paisa per square meter is Rs.508.20. Find the perimeter of the field if its sides are in the ratio 3:2 a) 121m b) 96m c) 55m d) 110m

Description : The cost of preparing a cricket ground of rectangular shape at 70 paisa per square meter is Rs.508.20. Find the perimeter of the field if its sides are in the ratio 3:2 a) 121m b) 96m c) 55m d) 110m

Last Answer : d) 110m

Find the number of divisors of 2475 that are not perfect squares? a) 14 b) 16 c) 20 d) 10

Description : Find the number of divisors of 2475 that are not perfect squares? a) 14 b) 16 c) 20 d) 10

Last Answer : a) 14

Which of the following represents the largest 4-digit number which can be added to 7249 in order to make the derived number divisible by each of 12,14,21,33 and 54? a) 9123 b) 9383 c) 8727 d) 8673

Description : Which of the following represents the largest 4-digit number which can be added to 7249 in order to make the derived number divisible by each of 12,14,21,33 and 54? a) 9123 b) 9383 c) 8727 d) 8673

Last Answer : b) 9383

A block A is dropped down a smooth inclined plane, while another identical block B is released for free fall from the same height a.block A will have higher velocity than block B while hitting the ground b.block B will hit the ground earlier. c.both will hit the ground simultaneously d.block A will hit the ground earlier e.107 dynes

Description : A block A is dropped down a smooth inclined plane, while another identical block B is released for free fall from the same height a.block A will have higher velocity than block B while hitting the ... . c.both will hit the ground simultaneously d.block A will hit the ground earlier e.107 dynes

Last Answer : b. block B will hit the ground earlier.

It is a 5 letter word if you take away first letter it is something you get from sun, if you remove second letter you will get something to eat, if you remove third letter you get a word you use in pointing at and if you remove the fourth letter you get something to drink. What is it? -Riddles

Description : It is a 5 letter word if you take away first letter it is something you get from sun, if you remove second letter you will get something to eat, if you remove third letter you get a word you use in pointing at and if you remove the fourth letter you get something to drink. What is it? -Riddles

Last Answer : Wheat.

A can hit a target three times in five shots, B two times in five shots and C three times in four shots. They fire a volley. -Maths 9th

Description : A can hit a target three times in five shots, B two times in five shots and C three times in four shots. They fire a volley. -Maths 9th

Last Answer : P(A) = \(rac{3}{5}\), P(B) = \(rac{2}{5}\), P(C) = \(rac{3}{4}\). In order that two shots may hit the target the following three mutually exclusive events are possible,(i) A and B hit the target and not C. (ii) B ... {100}\) + \(rac{12}{100}\) + \(rac{27}{100}\) = \(rac{45}{100}\) = \(rac{9}{20}.\)

I am a being with many faces. My first is peaceful and calm, but can kill you. My second is strong enough to smash ships but still fears the sun. My third flies when it's born and runs when it's dead. My fourth goes away and never returns. What am I? -Riddles

Description : I am a being with many faces. My first is peaceful and calm, but can kill you. My second is strong enough to smash ships but still fears the sun. My third flies when it's born and runs when it's dead. My fourth goes away and never returns. What am I? -Riddles

Last Answer : Water.

Four members of a band are walking to a night concert. They decide to take a shortcut, but must cross a bridge. Luckily they have one flashlight. Because of the varying size of their instruments, it takes each member a different amount of time to cross the bridge - it takes the first person one minute, the second person two minutes, the third person five minutes and the fourth person ten minutes. They must cross the bridge in pairs, travelling at the slower speed so if the one minute person went with the ten minute person, it would take a total of ten minutes. Since there is only one flashlight, one person must come back across the bridge, then another pair can cross. They only have 17 minutes to cross the bridge and still get to the concert on time. What order should they cross to get eve

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Last Answer : First, the one minute person and the two minute person must cross the bridge, for a total of two minutes. Then the one minute person should come back with flashlight - total of three ... minutes) and gets the one minute person and they cross together bringing the total to seventeen minutes.

Where the first shots of the Civil War were fired?

Description : Where the first shots of the Civil War were fired?

Last Answer : Fort Sumter, California.

A vertical spring-mass system has a mass of 0.5 kg and an initial deflection of 0.2 cm. Find the spring stiffness. A. 345 N/m B. 245 N/m C. 3452 N/mD. 2452 N/m

Description : A vertical spring-mass system has a mass of 0.5 kg and an initial deflection of 0.2 cm. Find the spring stiffness. A. 345 N/m B. 245 N/m C. 3452 N/mD. 2452 N/m

Last Answer : D. 2452 N/m