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

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

Two numbers are in the ratio 3 : 4. Their L.C.M. is 84. The greater number is 

The LCM of three different numbers is 120. Which of the following cannot be their HCF? 

Two pipes of length 36 metre and 40 metre are to be cut into equal pieces without leaving any extra length of pipe. Find the number of such pieces if pipes are to be cut of maximum length.

Four bells ring at the intervals of 5, 6, 8, and 9 seconds. All the bells ring simultaneously at the same time. They will again ring simultaneously after: 

The least number, which when divided by 4, 5 and 6 leaves remainder 1, 2 and 3 respectively is:

Three men step off together from the same spot. Their steps measure 63 cm, 70 cm and 77 cm respectively. The minimum distance each should cover so that all can cover the distance in complete steps is