Quantitative Aptitude - Arithmetic Ability Questions

If the age of Rahul is 5 years more than his friend Ajay's age and the age of Rahul's wife is 6 years less than Rahul, and Ajay's wife is 1 year older than Rahul's wife, then which of the following statements is true?

The rate of working of A and B are in the ratio of 2:3. The number of days taken by them to finish the work is in the ratio:

Select the odd word/letters/number/number pair from the given alternatives.

tan(A/2) is equal to

If 3x - 8(2 - x) = -19, then the value of x is

The average of 100 observations was calculated as 35.It was found later, that one of the observation was misread as 83 instead of 53. The correct average is :

2*[­0.3(1.3 + 3.7)] of 0.8 = ?

Which single discount will be equal to two successive discounts of 12% and 5%?