Quantitative Aptitude - Arithmetic Ability Questions

In the following question, select the odd letter/letters from the given alternatives.

Some girls can do a piece of work in 18 days. In how much time (in days) two times the number of such girls will complete thrice of the work?

Mohan starts to calculate sum of all odd natural number less than 83. What result does he get?

Simple interest on a certain sum of money for 3 years at 5% per annum is Rs. 5250. What will be the compound interest on that sum at the same rate for the same period?

If the side AB of an equilateral triangle ABC is equal to 12 cm. Calculate the length( in cm) of the AO, if O is the centroid of the triangle.

The ratio of total surface area and volume of a sphere is 1 : 7. This sphere is melted to form small spheres of equal size. The radius of each small sphere is 1/6th the radius of the large sphere. What is the sum (in cm2) of curved surface areas of all small spheres?

The square root of 3249 is

Two fractions are such that their product is ­9/10 and sum is ­13/40. What are the two fractions.