18 percent of the coal was destroyed in a coal mine. If only 492 tons of coal was received, then tell how much coal was destroyed?

Mr. Ankit invests 14% of his monthly income every month i.e. Rs.1,750 in shares, 8% in Insurance policies and 7% in fixed deposits. What is the total annual amount invested by him?

In a village, 70 percent of the households have a mobile. 20 percent of the households have TV and 15 percent of the families have both TV and mobile. If the total number of families is 116, then how many families have neither mobile nor TV?

60% boys are failed in History and 65% boys are failed in Geography while total 30% boys are failed in both the subjects. If total 1200 boys appeared in the examination then total how many boys are passed?

Some students (only boys and girls) from different schools1 appeared for an Olympiad exam. 20% of the boys and 15% of the girls failed the exam. The number of boys who passed the exam was 70 more than that of the girls who passed the exam'. A total of 90 students failed. Find the number of students that appeared for the exam.

If the radius of a circle is decreased by 50%, its area is reduced by

A man saves 20% of his  monthly salary. If an account of dearness of things he is to increase his monthly expenses by 20%, he is only able to save Rs. 200 per month. What is his monthly salary?

A man spends a part of his monthly income and saves the rest. The ratio of his expenditure to the saving is 61 : 6. If his monthly income is Rs .8710, the amount of his monthly saving is