Quantitative Aptitude - Arithmetic Ability Questions

If x+1x=5,then the value of x1+x+x2 is

A group of boys has an average weight of 36 kg. One boy weighing 42 kg leaves the group and another boy weighing 30 kg joins the group. If the average now becomes 35.7 kg, then how many boys are there in the group?

The average cost of 4 items in a shopping list is Rs 1,250. If one more item whose cost is Rs 2,000 is added to the list what will be the new average (in
Rs)?

Simple interest on a certain sum of money for 3 years at 8% per annum is half the compound interest on Rs. 16000 for 2 years at 10% per annum. The sum placed on simple interest is:

Vishal is 20 years younger to Arya. Twelve years hence Arya's age will be 1.25 times that of Vishal. Aryais now ......... years old.

Bipul is 16 years younger than Saibal. 12 years hence, Saibal's age will be 1.5 times that of Bipul. Saibal is now ___ years old.

Expand and simplify (3x + 2)2*(4x -­ 3) -­ (2x3 - 9x2 + 12x -­ 24)

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