Quantitative Aptitude - Arithmetic Ability Questions

The mean of 100 observations was calculated as 40. It was found later on that one of the observations was misread as 83 instead of 53. The correct mean is:

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 ?

What is the value of sec -2π/3 ?

If sin(A/2) = x, then the value of x is

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

The price of an article is cut by 7%, to restore it to its original value, the new price must be increased by

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

The alcohol and water in a mixture are in the ratio of 7 : 8 respectively. If 11 litre water is added to it, then the ratio of alcohol and water in the new mixture becomes 3 : 5. What is the total quantity (in litres) of the alcohol in the new mixture?