Simplify : $$ {9\over 13} ÷{18\over 26}÷{90\over 52}$$

The smallest positive integer n for which 864 x n is a perfect cube, is: 

Find the value of given expression.

3 – (– 6) {– 2 – 9 – 3} ÷ 7{1 + (– 2) (– 1)}

Find the value of x:
2³ × 3⁴ × 1080 ÷ 15 = 6^x

There are some boys and girls in a room. The square of the number of the girls is less than the square of the number of boys by 28. If there were two more girls, the number of boys would have been the same as that of the girls. The total number of the boys and girls in the room are

The value of   $$ {(0.03)^2 - (0.01)^2}\over 0.03-0.01 $$

(0.04)^-1.5 on simplification gives: 

If (a + b):(b + c):(c + a) = 7:6:5 and a + b + c = 27, then what will be the value of 1/a: 1/b :1/c?