PSLE
Four girls, Xuan, Kimberly, Wendy and Tina raised money for a charity. Xuan and Kimberly raised a total of $138. Together, Kimberly, Wendy and Tina raised a total of $240. The total amount of money raised by all 4 girls is 5 times the amount that Kimberly raised. How much money did Xuan raise?
Amount that Kimberly and Xuan raised = $138
Amount that Kimberly, Wendy and Tina raised = $240

Kimberly is the repeated identity.

Kimberly + Xuan = 138 --- (1)
Kimberly + Wendy + Tina = 240 --- (2)

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

(1) + (2)
(Kimberly + Xuan) + (Kimberly + Wendy + Tina) = 138 + 240
Kimberly + 4 girls = 378
1 u + 5 u = 378
6 u = 378

1 u = 378 ÷ 6 = 63

Amount that Xuan raised
= 138 - 1 u
= 138 - 63
= $75

Answer(s): $75