Recent questions tagged lcm-and-hcf

Description : The L.C.M of two numbers is 14 times their H.C.F . The sum of the L.C.M. and the H.C.F . is 600. If one number is 280 , then the other number is (a) 40 (b) 60 (c) 80 (d) 100

Last Answer : 80

Description : Find the greatest unit of time with which 5 hours 15 minutes and 8 hours 24 minutes can both be represented as integers. (a) 70 min. (b) 63 min. (c) 48 min. (d) 42 min.

Last Answer : 63 min. 

Description : The smallest number which when divided by 20, 25, 35 and 40 leaves a remainder of 14, 19 , 29 and 34 respectively is (a) 1994 (b) 1494 (c) 1394 (d) 1496

Last Answer : 1394 Hint: Note that 20 -4 = 6; 25 -19 = 6;35-29= 6;40- 34 = 6 Required number = L.C.M. of ( 20, 25, 35 and 40)-6

Description : Find the least number of five digits which is exactly divisible by 12, 15 and 18. (a) 1080 (b) 10080 (c) 10025 (d) 11080

Last Answer : 10080 Hint : The least number of 5 digits is 10000. L.C.M. of 12, 15 and 18 is 180 . On dividing 10000 is 100. => 10000 + 180- 100 = 10080 is divisible by 180.

Description : The largest numbers which divides 30, 78 and 102 to leave the same remainder in each case is (a)24 (b) 20 (c) 8 (d) 16

Last Answer : 24

Description : The sum of two numbers is 528 and their H.C.F is 33. What is the number of pairs of such numbers ? (a) 4 (b) 12 (c) 8 (d) 6

Last Answer : Ans 5. 4 Hint : Let the number be 33x and 33y where x and y are co-prime.

Description : Three measuring rods are 64 cm,80 cm and 96 cm in length . What is the least length of cloth that can can be measured exact number of times using any one of these rods? (a) 9.60 m (b) 8 m (c) 9.60 cm (d) 96 m

Last Answer : Ans 4. 9.60 m

Description : A gardener had a number of shrubs to plant in rows . At first he tried to plant 8, then 12 and then 16 in a row but he always had 3 shrubs left with him . On trying 7 shrubs he was left with none.Find the total number of shrubs.

Last Answer : Ans 3. L.C.M of 8,12,16 = 48 Now, 48 x 1 + 3 = 51 - not divisible by 7 48 x 2 + 3 = 99 - not divisible by 7 48 x 3 + 3 = 147 - not divisible by 7 Required number = 147

Description : The H.C.F of two numbers is 11 and their L.C.M is 7700. If one of these numbers is 275, then find the other number.

Last Answer : Ans 2. Product of two number s = product of their H.C.F. and L.C.M. required number = 11 X 7700/275 = 308

Description : Six bells commencing tolling together toll at intervals of 2, 3, 6, 8 , 10 and 12 seconds respectively.In 30 minutes how many times do they toll together?

Last Answer : Ans 1. L.C.M of 2, 4, 6, 8, 10 and 12 is 120. so, the bells will toll together after 120 seconds i.e. 2 minutes . In 30 minutes the bells toll together 30/2 + 1 times i.e. times.