PSLE
Four girls, Abi, Tiffany, Sarah and Yen raised money for a charity. Abi and Tiffany raised a total of $193. Together, Tiffany, Sarah and Yen raised a total of $187. The total amount of money raised by all 4 girls is 3 times the amount that Tiffany raised. How much money did Abi raise?
Amount that Tiffany and Abi raised = $193
Amount that Tiffany, Sarah and Yen raised = $187

Tiffany is the repeated identity.

Tiffany + Abi = 193 --- (1)
Tiffany + Sarah + Yen = 187 --- (2)

Amount that Tiffany raised = 1 u
Amount that 4 girls raised = 3 u

(1) + (2)
(Tiffany + Abi) + (Tiffany + Sarah + Yen) = 193 + 187
Tiffany + 4 girls = 380
1 u + 3 u = 380
4 u = 380

1 u = 380 ÷ 4 = 95

Amount that Abi raised
= 193 - 1 u
= 193 - 95
= $98

Answer(s): $98