Some students (only boys and girls) from different schools 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.

The east positive integer that should be subtracted from 3011 x 3012 so that the difference is a perfect square is-

Two men can complete a work in 9 days. How many men will be required to complete twice the work in 12 days?

Evaluate: $${-(4-6)^2-3(-2)+।-6।\over 18-9÷3×5}$$

1261 in 3 years at the rate of 5 percent annual interest on a sum of money. Interest is received by compound . money will be

A sum of money doubles itself at compound interest in 15 years. In how many years it  will become eight times?

If S denotes the area of the curved surface of a right circular cone of height h and semi vertical angle ∝ then S equals

Find the LCM of x and (x+3).