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

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

If 1.5a=0.04 b then find out the value of $$ {b-a\over b+a}$$.

A shopkeeper bought 240 ton rice. He sold 4/5th is at 37.5% profit, then find at what percentage profit or loss he should sell remaining rice, so as to gain 25% on the whole transaction? 

There are 240 workers and an amount of Rs. 2880 is to be divided among them. The ratio of total amount received to men and women is 5 : 4 and the ratio of the amount given to each man and each woman is 5 : 8. Find the number of men.

16 boys or 12 women can do a piece of work in 28 days. In how many days will the same work be done by 4 boys and 4 women, if they all work together?

The total of the ages of Kiran, Shantanu and Saransh is 93 years. Ten years ago, the respective ratio of their ages was 2 : 3 : 4 . What is the present age of Saransh?

The value of $$ {2(1-sin^{2}θ)}+{2(1-cos^{2}θ)}$$. 

10 men can finish painting a wall in 8 days. How many more men will be needed if the painting work is to be finished in 4 days?