PSLE
Four girls, Rachel, Irene, Kathy and Zoe raised money for a charity. Rachel and Irene raised a total of $101. Together, Irene, Kathy and Zoe raised a total of $379. The total amount of money raised by all 4 girls is 5 times the amount that Irene raised. How much money did Irene raise?
Amount that Irene and Rachel raised = $101
Amount that Irene, Kathy and Zoe raised = $379

Irene is the repeated identity.

Irene + Rachel = 101 --- (1)
Irene + Kathy + Zoe = 379 --- (2)

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

(1) + (2)
(Irene + Rachel) + (Irene + Kathy + Zoe) = 101 + 379
Irene + 4 girls = 480
1 u + 5 u = 480
6 u = 480

1 u = 480 ÷ 6 = 80

Amount that Irene raised
= 1 u
= $80

Answer(s): $80