Quantitative Aptitude - Arithmetic Ability Questions

If 7x ­- 5y = 13 and 2x -­ y = 5, then (x -­ y) is

If a(a + b + c) = 45, b(a + b + c) = 75 and c(a + b + c) = 105, then what is the value of (a2 + b2 + c2 )?

The selling price of an article is 8/5th of its cost price. Then the gain percentage is

If x - y = -9 and xy = -20, then find x2 + y2 ?

If a+1b= b+1c = c+1a (a , b, c are not equal) then the value of abc = 

What is the value of [(cos32θ + 3 cos 2θ)÷(cos6θ – sin6θ)]?

Roshan's current age is three years less than 1.5 times that of Usha's. 12 years ago Usha's age was three years more than half of Roshan's age. What is Roshan's present age in

A sum fetched a total simple interest of Rs. 7728 at the rate of 7% per year in 8 years. What is the sum?