At an entertainment centre, the cost for using a particular video game is \(\$0.40\) per minute. The number of minutes for which people use the video game has mean 15 and variance 9.

(a) Find the mean and variance of the amount people pay for using the video game. [3]

Each day, 35 people independently use the video game.

(b) Find the mean and variance of the total amount paid by 35 people. [3]