Quantitative Aptitude - Arithmetic Ability Questions

If 1 + (1/2) + (1/3) + ... + (1/20) = k, then what is the value of (1/4) + (1/6) + (1/8) + ... + (1/40)?

If 2A = 3B = 8C; What is A : B : C?

A parallelogram PQRS, the length of whose sides are 8 cm and 12 cm, has one diagonal 10 cm long Ile length of the other diagonal is approximately:

The average of 25 consecutive odd integers is 55. The highest of these integers is

What least value must be assigned to '*' so that the numbers 451 *  603 is exactly divisible by 9?

The ratio of ages of father and son is 7:2. Five years ago the product of their ages was 150. What is the age of the father?

Price of diesel increased from Rs 45/litre to Rs 50/litre. How much should the consumption of diesel be reduced (in %) so as to increase expenditure by only 5%?

What approximate value should come in place of the question mark (?) in the following equation (Note: You are not expected to calculate the exact value)?

[(7.99)2–(13.001)2+(4.01)3]2=?