Quantitative Aptitude - Arithmetic Ability Questions

The average age of eight teachers in a school is 40 years. A teacher among them died at the age of 55 years whereas another teacher whose age was 39 years joins them. The average age of the teachers in the school now is (in years)

The sum of ages of 4 children born at intervals of 4 years each is 60. What is the age of the youngest child?

ABC is a right angled triangle in which ∠A = 90°, AB = 5 cm and AC = 12 cm. What is the approximate volume (in cm3) of the double cone formed by rotating the triangle about its hypotenuse?

The compound interest earned in two years at 12% per annum is Rs 10176. What is the sum (in Rs) invested?

Which one of the following is an irrational number?

Δ DEF is right angled at E. If m ∠D = 30°. What is the length (in cm) of DE, if EF = 2√3 cm?

If SinX-CosX=1, where 'X' is an acute angle, the value of SinX+CosX is

A sum of Rs 10000 becomes Rs 14641 when invested at compound interest at the yearly interest rate of 20% per annum. If the compounding is done half yearly, then for how many years was the sum invested?