Which of the following numbers is divisible by 25?

In a class, there are ' z ' students. Out of them ‘x’ are boys. What part of the class is composed of girls? 

The value of (81)3.6 * (9)2.7/ (81)4.2 * (3) is __

In a division sum, the divisor is ten times the quotient and five times the remainder. If the remainder is 46, find the dividend.

A four digit number is formed by writing a two digit number together twice like: 15:15, -3737 etc. A number of this form will be exactly divisible by which of the following numbers 

A number consists of two digits. If the number formed by interchanging the digits is added to the original number, the resulting number (i.e. the sum) must be divisible by

many times will the buttons of a typewriter be pressed to write the numbers 121 to 1346?

Find the greatest number 23a68b, which is divisible by 3 but NOT divisible by 9.