A boy has 120 balls of which some are white and the remaining are black. If the percentage of white balls is 45%, find the number of black balls he has.

The price of sugar is increased by 21%. A person wants to increase his expenditure by 12% only. By what percent, correct to one decimalplace, should he reduce his consumption?

If the length of a rectangle is increased by 40%, and the breadth is decreased by 20%,then the area of the rectangle increases by x%. Then the value of x is:

A shopkeeper marks the price of the article in such a way that after allowing 28% discount, he wants a gain of 12%. If the marked price is ₹224. then the cost price of the article is:

The price of sugar is increased by 17%. A person wants to increase his expenditure by 8% only. By what percent should he decrease his consumption, nearest to one decimal place?

The price of sugar is increased by 24%. A person wants to increase his expenditure by 15% only. By what percentage, correct to one decimal place, should he reduce his consumption?