What is the LCM (least common multiple) of 57 and   93?

The product of the LCM and HCF of two numbers is 24. The difference of the two numbers is 2. Find the numbers? 

If the least common multiple(LCM) of two numbers is 231, the Highest common multiple(H.C.F)  of both numbers is 11 and the first number is 77, then the second number is

What is the L.C.M of 12, 23, 24?

The HCF and LCM of two numbers are 12 and 924 respectively. Then the number of such pairs is: 

What is the HCF of 16, 72 and 28 ?

The traffic lights at three different road crossings change after 24 seconds, 36 seconds and 54 seconds respectively. If they all change simultaneously at 10 : 15 : 00 AM, then at what time will they again change simultaneously? 

The least number which when divided by 4, 6, 8, 12 and 16 leaves a remainder of 2 in each case is: