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

The product of two numbers is 2028 and their HCF is 13. The number of such pair is-

If the product of two numbers is 4941 and their LCM is 81, then their HCF is:

Find the LCM of the fractions $${2\over 5}$$, $${3\over 7}$$ and $${4\over 9}$$

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.

Three numbers which are co-prime to one another are such that the product of the first two is 551 and that of the last two is 1073. The sum of the three numbers is: 

If (x + k ) is the common factor of x² + ax + b and x² + cx + d , then what is k equal to ?

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