Quantitative Aptitude - Arithmetic Ability Questions

What is the value of xy if x - y = 3 and x2+y2=15?

If the equation 4x + 3y + 5 = 0 and 6x - ky - 7 = 0 have no solution, then the value of k is

What is the compound interest (in Rs) for 1 year on a sum of Rs 20000 at the rate of 40% per annum compounding half yearly?

The compound interest earned in two years at 15% per annum is Rs 20640. What is the sum invested (in Rs)?

Reflection of the point (2,­7) in the y­axis is

Rahul’s salary is 40% of Mohit’s salary. If Rahul’s salary is increased by 60% and Mohit’s salary is decreased by 20%, then Rahul’s salary will be how much percentage of Mohit’s salary?

Meghnad can do a piece of work in 45 hours. If he is joined by Jayshri, who is 50% more efficient, in what time will they together finish the work?

A shopkeeper increases the price of an object by 40% and then sells it at 25% discount on the marked price. If the selling price of such an object be Rs. 2100, its cost price for the shopkeeper was ?