PSLE
Four girls, Abi, Winnie, Cathy and Olivia raised money for a charity. Abi and Winnie raised a total of $76. Together, Winnie, Cathy and Olivia raised a total of $116. The total amount of money raised by all 4 girls is 5 times the amount that Winnie raised. How much money did Cathy and Olivia raise?
Amount that Winnie and Abi raised = $76
Amount that Winnie, Cathy and Olivia raised = $116

Winnie is the repeated identity.

Winnie + Abi = 76 --- (1)
Winnie + Cathy + Olivia = 116 --- (2)

Amount that Winnie raised = 1 u
Amount that 4 girls raised = 5 u

(1) + (2)
(Winnie + Abi) + (Winnie + Cathy + Olivia) = 76 + 116
Winnie + 4 girls = 192
1 u + 5 u = 192
6 u = 192

1 u = 192 ÷ 6 = 32

Total amount that Cathy and Olivia raised
= 116 - 1 u
= 116 - 32
= $84

Answer(s): $84