PERMUTATIONS AND COMBINATIONS Question

A student has to answer 10 questions, choosing at least 4 from each of Parts A and B. If there are 6 questions in Part A and 7 in Part B, in how many ways can the student choose 10 questions?

LCM & HCF Sample Questions

1.The product of two 2 digit numbers is 2028 and their HCF is 13. What are the numbers ?

A. 26, 78         B. 39, 52         C. 13, 156       D. 36, 68

2.Six bells commence tolling together and toll at intervals of 2, 4, 6, 8 10 and 12 seconds respectively. In 30 minutes, how many times do they toll together ?

A. 4                  B. 10               C. 15                D. 16

3.N is the greatest number which divides 1305, 4665 and 6905 and gives the same remainder in each case. What is the sum of the digits in N?

A. 4                  B. 3                  C. 6                  D. 5

4.Which greatest possible length can be used to measure exactly 15 meter 75 cm, 11 meter 25 cm and 7 meter 65 cm

A. 45cm                      B. 255cm                    C. 244cm                    D. 55cm

5.Let N be the greatest number that will divide 1305, 4665 and 6905, leaving the same remainder in each case. Then sum of the digits in N is:

A. 4                  B. 5                  C. 6                  D. 8

6.A, B and C start at the same time in the same direction to run around a circular stadium. A completes a round in 252 seconds, B in 308 seconds and c in 198 seconds, all starting at the same point. After what time will they again at the starting point ?

A. 36 minutes 22 seconds                B. 46 minutes 22 seconds

C. 36 minutes 12 seconds                D. 46 minutes 12 seconds

7.An electronic device makes a beep after every 60 sec. Another device makes a beep after every 62 sec. They beeped together at 10 a.m. The time when they will next make a beep together at the earliest, is

A. 10:28 am                B. 10:30 am                C. 10:31 am                D. None of above

 8.What is the LCM of 2/3, 5/6 and 4/9 ?

A. 3/10                       B. 3/20                       C. 10/3                       D. 20/3

9.The smallest number which when diminished by 7, is divisible 12, 16, 18, 21 and 28 is:

A. 1008                       B. 1015                       C. 1022                       D. 1032

10.What is the HCF of 9/10,12/15, 18/35 and 21/40 is :

A. 3/5                                     B. 252/5                     C. 1/280                     D. 63/700