Quantitative Aptitude - Arithmetic Ability Questions

The average marks obtained by a group of 10 students were 20. One student left the group as a result of which the average of the remaining students rose to 21. But another student joined, as a result of which the average marks of the group dropped a bit and became 20.6. What were the average marks obtained by the student who left and the one who joined?

If the average age of four children is 12 years and the average age of these children and their fathers is 20 years, what is the age of the father?

The value of 1+tan2∅(1-sin2∅) is

If x – 4y = 0 and x + 2y = 24, then what is the value of (2x + 3y)/(2x – 3y)?

If secA/√(sec2A ­- 1) = x, then value of x is

If a -­ b = 6 and ab =16, then a3 -­ b3 is

In ΔDEF measure of angle E is 90 deg. If sinD = 15/17, and DE = 4cm, then what is the length (in cm) of side EF?

The length of one side and the diagonal of a rectangle are 7 cm and 25 cm respectively. Find its area (in cm²)