Quantitative Aptitude - Arithmetic Ability Questions

The average height of 30 boys out of a class of 50 is 160 cm. If the average height of the remaining boys is 165 cm, the average height of the whole class (in cm) is:

The line passing through point (-3,1) and point (x,5) is parallel to the line passing through point (-2,-1) and point (6,3). What is the value of x?

Product of digits of a 2-digit number is 15. If we add 18 to the number, the new number obtained is a number formed by interchange of the digits. Find the number.

Two numbers are 40% and 80% lesser than a third number. By how much percent is the second number to be enhanced to make it equal to the first number?

Of the 5 numbers whose average is 76, the first is 3/7 times the sum of other 4. The first number is

What is the equation of line whose slope is -1/2 and passes through the intersection of the lines x - y = -1 and 3x - 2y = 0?

The sum of a fraction and 7 times its reciprocal is 11/2. What is the fraction?

In 2 years at simple interest the principal increases by 8%. What will be the compound interest earned (in Rs) on Rs 10 lakhs in 2 years at the same rate?