Quantitative Aptitude - Arithmetic Ability Questions

If a, b and c are positive integers such that 1a+1b+1c+12 = 1623, then what is the mean of a, b and c?

What is the value of cos [(180 – θ)/2] cos [(180 – 9θ)/2] + sin [(180 – 3θ)/2] sin [(180 – 13θ)/2]?

If the average age of 20 students in Class-I is 10 years and average age of 25 students in Class II is 12 years, find the average age (in years) of all students.

If a + b = 9 and a2+ b2= 61, then ab is

If compound interest received on a certain amount in the 2nd year is Rs 1200, what will be the compound interest (in Rs) for the 4th year on the same amount at 10% rate of interest?

If the measure of the interior angle of a regular polygon is 1800, then how many sides does it have?

If the product of two numbers is 3026 and their LCM is 89, then their HCF is :

A tyre is sold at three successive discounts of 20%,30%, and 20%. What is the net discount (in percentage)