There are four bells which ring at an interval of 15 minutes, 25 minutes, 35 minutes and 45 minutes respectively. If all of them ring at 9 A.M., how many more times will they ring together in the next 72 hours ?

The HCF and LCM of two numbers p and q are 44 and 4620 respectively. When p is divided by 55, the quotient is 4 and remainder is 0. What is the value of q?

If x is the HCF and y is the LCM of 3/5, 6/25, 9/20, 27/50 then which one of the following is correct?

Let L be the LCM and Hbe the HCF of two given numbers. L and H are in the ratio 3 : 2. If the sum of the two numbers is 45, then what is the product of the numbers?

The least multiple of 7, which leaves a remainder of 4, when divided by 6, 9, 15 and 18 is:

Three number are in the ratio of 3 : 4 : 5 and their L.C.M. is 2400. Their H.C.F. is: