Quantitative Aptitude - Arithmetic Ability Questions

Find the least common multiple of 15 and 12?

If (x/a) + (y/b) = 3 and (x/b) – (y/a) = 9, then what is the value of x/y?

In a computer game, there are builders and destroyers. Together there are 20 of them. Some of them try to build a wall around a castle while the rest try to demolish it. Each of the builders can build the wall alone in 15 hours while any of the destroyers can demolish it in 10 hours. If all 20 builders and destroyers are made active when there is no wall and the wall gets built in 3 hours, how many of them are destroyers?

If A = 2B = 4C; what is the value of A : B : C?

When a discount of 20% is given on a pizza, the profit is 32%. If the discount is 18%, then the profit is

A student multiplied a number by 4/5 instead of 5/4. What is the percentage error in the calculation?

If the radius of a circle is increased by 29% its area increases by

Shiv sold a shirt for Rs. 184 at a loss of 8%. To make a profit of 5% he should have sold the shirt for