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)

If the arithmetic mean of two numbers is 7 and the geometric mean of the same two numbers is 2√10. Then find the numbers x and y respectively, such that x>y.

A sum of money becomes 77/50 of itself in 18/5 years when invested at simple interest. What is the rate (in percentage) of interest per annum?

Find the difference between place value and face value of 7 in 589573212.

What is the reflection of the point (6, -3) in the line y = 2?

The areas of two similar triangles ΔABC and ΔPQR are 36 sq cms and 9 sq cms respectively. If PQ = 4 cm then what is the length of AB (in cm)?

What is the length of the side of an equilateral triangle, if its area is 36√3 sq cm?

Assuming that the numbers in each of the following figures follow a similar pattern, select the option that can replace the question mark (?) in figure C.