The duration of contact of chlorine with water before it is served to the first consumer, should be at least (A) 10 to 15 minutes (B) 15 to 20 minutes (C) 20 to 30 minutes (D) 30 to 40 minutes

The duration of contact of chlorine with water before it is served to the first consumer, should be 

at least 

(A) 10 to 15 minutes 

(B) 15 to 20 minutes 

(C) 20 to 30 minutes 

(D) 30 to 40 minutes 

by

1 Answer

Answer :

(C) 20 to 30 minutes 

by

Related questions

A barrier has four inlets A, B, C and D. The barrier can be filled in 24 minutes through the first three inlets and it can be filled in 30 minutes through the second, the third and fourth inlet also it can be filled through the first and the fourth inlet in 40 minutes. How much time required to fill up the barrier by all the four inlets? A) 10 mins B) 15 mins C) 20 mins D) 25 mins E) None of the Above

Description : A barrier has four inlets A, B, C and D. The barrier can be filled in 24 minutes through the first three inlets and it can be filled in 30 minutes through the second, the third and fourth inlet also it can be ... all the four inlets? A) 10 mins B) 15 mins C) 20 mins D) 25 mins E) None of the Above

Last Answer : C (1/A + 1/B + 1/C) = 1/24 …(i) (1/B + 1/C + 1/D) = 1/30 …(ii) (1/A + 1/D) = 1/40…(iii) From eqn (i) and (ii) (1/A – 1/D) = 1/120…(iv) From eqn (iii) and (iv) A=60,D=120. Let the time taken to full the tank = s S(1/A + 1/B +1/C +1/D)= 1 S(1/24+1/120) = 1 S= 20 mins

The percentage of chlorine in fresh bleaching powder is roughly (A) 50 to 60 (B) 30 to 35 (C) 40 to 50 (D) 20 to 25

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Last Answer : (B) 30 to 35

A unit hydrograph is a hydrograph of a rain storm of a specified duration resulting from a run-off of (A) 15 mm (B) 20 mm (C) 25 mm (D) 30 mm

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Ravi walks to and fro to a Gym. He spends 30 minutes in gym. If he walks at speed of 20 km an hour, he returns to home at 8.00 a.m. If he walks at 30 km an hour, he returns to home at 7.30 a.m. How fast must he walk in order to return at 7.15 hours? a) 40 km/hr b) 30 km/hr c) 60 km/hr d) 50 km/hr

Description : Ravi walks to and fro to a Gym. He spends 30 minutes in gym. If he walks at speed of 20 km an hour, he returns to home at 8.00 a.m. If he walks at 30 km an hour, he returns to home at 7.30 a.m. How fast must he walk in order to return at 7.15 hours? a) 40 km/hr b) 30 km/hr c) 60 km/hr d) 50 km/hr

Last Answer :  A As per the question, let D be the total distance and ‘t’ is the time taken. So we have: D=20t 20t =30(t-0.5) 20t=30t-15 10t=15 t=3/2 D= 30 km Now, for the condition given we have: 30=S(t-3/4) 30=S(3/2-3/4) 30=S((6-3)/4) 30=S(3/4) S=40 km/hr

The detention period in a septic tank is assumed (A) 20 minutes (B) 25 minutes (C) 30 minutes (D) 40 minute

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Two concave lenses of 60 cm focal length are cemented on either side of a convex lens of 15 cm focal length. The focal length of the combination is (A) 10 cm (B) 20 cm (C) 30 cm (D) 40 cm

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Last Answer : (C) 30 cm 

The bearing capacity of granite is generally (A) 5 to 10 kg/cm2 (B) 15 to 20 kg/cm2 (C) 30 to 35 kg/cm2 (D) 40 to 45 kg/cm2

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Last Answer : C. 30

For a controlled flight before departure, a flight plan must be filed at least: a. 50 minutes before off-block time b. 60 minutes before departure c. 10 minutes before departure d. 30 minutes before off-block time

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Last Answer : b. 60 minutes before departure

For a controlled flight before departure, a flight plan must be filed at least: a. 50 minutes before off-block time b. 60 minutes before departure c. 10 minutes before departure d. 30 minutes before off-block time

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Last Answer : b. 60 minutes before departure

Three pipes P, Q and R can fill a tank from empty to full in 40 minutes, 15 minutes, and 30 minutes respectively. When the tank is empty, all the three pipes are opened. P, Q and R discharge chemical solutions X, Y and Z respectively. What is the proportion of the solution Y in the liquid in the tank after 5 minutes? a) 8 / 15 b) 7 / 15 c) 8 / 17 d) 6 / 13 e) 8 / 13

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The drainage area of a town is 12 hectares. Its 40% area is hard pavement ( K = 0.85), the 40% area is unpaved streets (K = 0.20) and the remaining is wooded areas (K = 0.15). Assuming the time of concentration for the areas as 30 minutes and using the formula Ps = 900/(t + 60) the maximum run off is A. 0.10 cumec B. 0.12 cumec C. 0.15 cumec D. 0.20 cumec

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The solution of radiator should be drained out when the engine has run for a) 10 to 15 minutes b) 15 to 20 minutes c) 20 to 25 minutes d) 25 to 30 minutes

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What is the setting for most autoclaves?a. 121oC at 15 psi for 15-30 minutes b. 100oC at 10 psi for 10-20 minutes c. 110oC at 21 psi for 20-30 min d. 150oC at 20 psi for 10-15 minutes

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A great banquet was prepared for a Roman emperor and his courtiers. 22 Dormice, 40 Larks' Tongues, 30 Flamingos and 40 Roast Parrots were served.How many portions of Boiled Ostrich were served? -Riddles

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Last Answer : 42. Each vowel is worth 2 and each consonant 4, so Dormice gives 22, ect.

A,B are start walking around a Circular park of radius 70m. They start at the same point, and A goes clockwise at 10m/s, while b goes anti-clockwise at 20m/s.How many times will they cross each other at the starting point if they walk for 30 minutes? a) 20 b) 40 c) 60 d) 80 e) None of the above

Description : A,B are start walking around a Circular park of radius 70m. They start at the same point, and A goes clockwise at 10m/s, while b goes anti-clockwise at 20m/s.How many times will they cross each other at the starting point if they walk for 30 minutes? a) 20 b) 40 c) 60 d) 80 e) None of the above

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A,B are start walking around a Circular park of radius 70m. They start at the same point, and A goes clockwise at 10m/s, while b goes anti-clockwise at 20m/s.How many times will they cross each other at the starting point if they walk for 30 minutes? a) 20 b) 40 c) 60 d) 80 e) None of the above

Description : A,B are start walking around a Circular park of radius 70m. They start at the same point, and A goes clockwise at 10m/s, while b goes anti-clockwise at 20m/s. How many times will they cross each other at the starting point if they walk for 30 minutes? a) 20 b) 40 c) 60 d) 80 e) None of the above

Last Answer : Radius = 70m, So circumference = 2 (22/7) 70 =440m Relative speed = 10 +20 = 30m/s They will meet everytime at the starting point when the distance covered by both put together is a multiple of 440 ... =1800/44 =40.9 So they will meet 40 times (we need to ignore the decimal part). Answer : b

Pipe A can fill an empty tank in 20 minutes and Pipe B in 30 mins and Pipe C can empty the same in 40 mins. If all of them work together, find the time taken to fill the tank? (a) 17 1/7 mins (b) 20 mins (c) 8 mins (d) none of these

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Last Answer : (a) 17 1/7 mins

The process of mixing, transporting, placing and compacting concrete using Ordinary Port land Cement should not take more than (A) 30 minutes (B) 40 minutes (C) 60 minutes (D) 90 minutes

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Last Answer : Answer: Option A

In every cell, the number of tRNA molecules is at least (A) 10 (B) 20 (C) 30 (D) 40

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In mixed farming at least — % gross income contributed by livestocks. a. 10 b. 20 c. 30 d. 40

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Last Answer : a. 10

The duration of action of insulin-zinc suspension (lente insulin) is: A. 2–4 hours B. 8–10 hours C. 20–24 hours D. 30–36 hours

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By adding 1 ml of Orthotolidine solution to 100 ml chlorinated water taken after contact period, the residual chlorine makes the colour of solution (A) Yellowish (B) Greenish (C) Bluish (D) Reddish

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Last Answer : (A) Yellowish

Duration of short hooter is…….. (a) 5 seconds* (b) 10 seconds (c) 15 seconds (d) 20 seconds

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If four fires break out in a city of population 40 lakhs and if each hydrant has three streams and duration of each fire is four hours, the total quantity of water required, is (A) 1880 kilo litres (B) 2880 kilo litres (C) 3880 kilo litres (D) 4880 kilo litres

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Last Answer : (B) 2880 kilo litres 

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Last Answer : Answer: 167 minutes.

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Last Answer : (ii) 20 minutes after pouring*

A bike starts with a speed of 60 km/hr at 8a.m. Due to the problem in engine it reduces its speed as 20 km/hr for every 1 hour. After 9 am, the time taken to covers 15 km is: a) 13 minutes and 20 seconds b) 15 minutes and 09 seconds c) 18 minutes and 15 seconds d) 22 minutes and 30 seconds

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Last Answer : 15 min

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50'. What number is missing? -Riddles

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Last Answer : 22

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Last Answer : d).15-45

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The sum of the ages of two persons A and B is 50. 5 years ago, the ratio of their ages was 5/3. The present age of A and B are (A) 30, 20 (B) 35, 15 (C) 38, 12 (D) 40, 10

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A cylindrical ejector having its height 2 m fills after every 10 minutes with a peak sewage discharge of 0.0157 cumec. The diameter of the ejector chamber, is A. 2.30 m B. 2.40 m C. 2.45 m D. 2.50 m

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Last Answer : (a) (i) only

A tank is 1/4th full. Two pipes which fill the tank in 30minutes and 40 minutes respectively are opened simultaneously. After 10 minutes, a third pipe which empties the full tank in 60 minutes is also opened. In how many minutes the tank will be full? A) 14 B) 12 C) 15 D) 17

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Clay and silt content in a good brick earth must be at least (A) 50 % (B) 40 % (C) 30 % (D) 25 %

Description : Clay and silt content in a good brick earth must be at least (A) 50 % (B) 40 % (C) 30 % (D) 25 %

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