Mrs Tay sold basketballs and netballs. Each basketball cost $21 each and each netball cost 3/7 as much as the basketball. Mrs Tay sold 1/3 of the balls and collected $2070. 2/5 of the balls sold were basketballs.
a) How many netballs were sold?
b) How much more money did Mrs Tay receive from the sales of the basketball?