Direction: what should come in place at question mark(?).

$$ {4\over 7}×{2{4\over 5}÷{2\over 5}=?}$$

By what least number should 4320 be multiplied so as to obtain a number which is perfect cube? 

Find the value of $$ {5^{1\over2}-[3^{1\over4}+6-4÷2]}$$

Find the value of given equations

$$\left({216\over1} \right) ^{-{2\over3}}÷\left({27\over1} \right) ^{-{4\over3}}=? $$

In a group of 15 women, 7 have nose studs, 8 have ear rings and 3 have neither. How many of these have both nose studs and ear rings? 

The least number, by which 1944 must be multiplied so as to make the result a perfect cube is 

On simplification of   $$ {(2.664)^2-(2.356)^2\over0.288}$$

Direction: What approximate value will come in place of the question mark (?) in the following question? (You are not expected to calculate the exact value)

(31.99)^1/5 × (80.78)^1/4 × (5.15)² = ? × 2.29