Which Indian holds the record of playing the highest

Let N be the greatest number that will divide 86, 112, 138 leaving the same remainder in each case. Then sum of the digits in N is:

The product of two numbers is 504 and their HCF is 6. Total number of such pairs of numbers is?     

The HCF of two numbers is 48, and their LCM is 1440. If one of the numbers is 576, find the other number.

The sum of two numbers is 126 and their HCF is 14. Total number of such pairs of numbers is?     

Find the LCM of 14, 20 and 30.

If the highest common factor of two numbers is 12, then which of the following may be the least common multiple of the numbers?

Find the least common multiple of (16/20), (8/10), and (4/5).

A circular wire of diameter 63 cm is folded in the shape of a rectangle whose sides are in the ratio 5:4. Find the area enclosed by the rectangle.

A dealer purchased 16 gadgets at Rs. 30 each. He sold 6 at 20% profit, 4 at 15% loss, and the rest at 10% profit. Compute the overall profit or loss.