Quantitative Aptitude - Arithmetic Ability Questions

The sum of the ages of father and a son presently is 70 years. After 10 years, the son's age is exactly half that of the father. What are their ages now?

The average age of a class of 39 students is 15 years. If the age of the teacher is included, then the average increases by 3 months. Find the age of the teacher.

If a:b = 5:8, find the value of (6a -­ 5b)/(a + 2b).

Line segment AB is parallel to line segment CD. AD intersects BC in E. If lengths of AE, BC and ED are 12 cm, 12 cm and 18 cm respectively, what is the length of EC?

At what rate of compound interest per annum will a sum of Rs 10000 become Rs 12321 in 2 years?

The ratio of milk and water in three samples is 1 : 3, 3 : 5 and 11 : 5. A mixture containing equal quantities of all three samples is made. What will be the ratio of milk and water in the new mixture?

Ehsaan is twice as good a worker as Kamal and together they finish a piece of work in 29 days. In how many days will Kamal, working alone, finish the work?

A piece of work was finished by A, B and C together. A and B together finished 60% of the work and B and C together finished 70% of the work. Who among the three is most efficient?