PSLE
Four girls, Irene, Wendy, Yoko and Tina raised money for a charity. Irene and Wendy raised a total of $144. Together, Wendy, Yoko and Tina raised a total of $390. The total amount of money raised by all 4 girls is 5 times the amount that Wendy raised. How much money did Yoko and Tina raise?
Amount that Wendy and Irene raised = $144
Amount that Wendy, Yoko and Tina raised = $390

Wendy is the repeated identity.

Wendy + Irene = 144 --- (1)
Wendy + Yoko + Tina = 390 --- (2)

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

(1) + (2)
(Wendy + Irene) + (Wendy + Yoko + Tina) = 144 + 390
Wendy + 4 girls = 534
1 u + 5 u = 534
6 u = 534

1 u = 534 ÷ 6 = 89

Total amount that Yoko and Tina raised
= 390 - 1 u
= 390 - 89
= $301

Answer(s): $301