A man works for certain hours. If his hourly payment increase by 20%, what percent of working hours he may reduce so that total income remain unchanged?

A depositor deposited Tk. 4,000 at x% simple interest and Tk. 5,000 at y % simple interest. He received annual interest of Tk. 320 on his deposited amounts at the year end. If he could deposit Tk. 5,000 at x% simple interest and Tk. 4,000 at y% simple interest, he would receive annual interest of Tk. 310. Find the value of x and y.

Working together pipe P, R and T can fill a trunk in 5 hours. Working together P and R can fill it in 7 hours. Find in how many hours T can fill it?

A box contains 5 green, 4 yellow and 3 white balls. Three balls are drawn at random. What is the probability that they are not of same colour?

There was a shipment of cars. Out of which half was black in colour. Remaining cars were equally blue, white and red. 70% of black cars, 80% of blue cars, 30% of white cars, 40% of red cars were sold. What percentage of total cars were sold?

A train passes a man in 3 second, and another train from opposite direction pass the man 4 second, both train same length. How long time need to pass the train each other?