Level 2
Zoe paid a total of $72 for an eraser, a ruler and a pen. The eraser cost 27 of the total cost of the ruler and the pen. The pen cost 15 of the total cost of the eraser and the ruler. Find the total cost of the pen and the eraser.
Level 1 PSLE
Charles has a number of 10¢, 20¢ and 50¢ coins in the ratio 4 : 2 : 1. The total value of all the coins is $156. What is the total value of the 20¢ coins?