The number of pairs of natural numbers the difference of whose squares is 45 will be –

What value will come in place of question mark (?) in the questions given below?
6⁹ × 36 ÷ 7776 = 6^? ÷ 216 

What should be added at least in 1140 so that it becomes a perfect square?

The third proportional of two numbers 9 and  24 is

The sum of two digit number is 16. If the digit is interchanged the number is formed 18 less than the original number. Find the original number.

Two numbers are respectively 30% and 40% less than a third number. What percent is the first number of the second?

The numerator of a fraction is 4 less than its denominator. If the numerator is decreased by 2 and the denominator is increased by 1, the denominator becomes eight times the numerator. Find the fraction? 

x is a five - digit number. The digit in ten thousand's place is 1. The number formed by its digits in unit's and ten's places is divisible by 4. The sum of all the digits is divisible by 3 . If 5 and 7 also divide x, then x will be: