Quantitative Aptitude - Arithmetic Ability Questions

A can do a piece of work in 8 days and B can do it in 10 days seperately. How many days would it take for both A and B to finish the same work together?

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.

The profit (in Rs.) after selling an article for Rs.524 is the same as the loss (in Rs.) after selling it for Rs.452. The cost price of the article is:

The sum of thrice a number and twice its reciprocal is 97/4. What is the number?

A, B and C can finish a job working alone in 20, 30 and 60 days respectively. They all work together for 1 day, then A and B quit. How many days C working alone will take to finish the remaining part of the job?

The average height of 50 bats is 126 cm. Some bats of average height 120 cm are removed. If the new average height is 130 cm, then how many bats are remaining?

Two mixtures have milk and water in the ratio 1 : 4 and 3 : 2 respectively. In what ratio two types of mixtures have to be mixed to get a new mixture having ratio of milk and water as 1 : 1?

PQ and RS are common tangents to two circles intersecting at A and B. AB, when produced both sides, meet the tangents PQ and RS at X and Y, respectively. If AB = 3 cm, XY = 5 cm, then PQ (in cm) will be