The radius of a circle is increasing at the rate of 0.02cms^-1. Find the rate at which the area is increasing when the radius of the circle is 7cm.

Find the mean of t + 2, 2t - 4, 3t + 2 and 2t.

The mean of seven numbers is 10. If six of the numbers are 2, 4, 8, 14, 16 and 18, find the mode.

\(\begin{array}{c|c}Age & 20 & 25 & 30 & 35 & 40 & 45 \\
\hline \text{No. of people} & 3 & 5 & 1 & 1 & 2 & 3 \end{array}\)

Calculate the median age of the frequency distribution in the table above