PSLE
Four girls, Cindy, Pamela, Vanessa and Yoko raised money for a charity. Cindy and Pamela raised a total of $129. Together, Pamela, Vanessa and Yoko raised a total of $143. The total amount of money raised by all 4 girls is 3 times the amount that Pamela raised. How much money did Cindy raise?
Amount that Pamela and Cindy raised = $129
Amount that Pamela, Vanessa and Yoko raised = $143

Pamela is the repeated identity.

Pamela + Cindy = 129 --- (1)
Pamela + Vanessa + Yoko = 143 --- (2)

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

(1) + (2)
(Pamela + Cindy) + (Pamela + Vanessa + Yoko) = 129 + 143
Pamela + 4 girls = 272
1 u + 3 u = 272
4 u = 272

1 u = 272 ÷ 4 = 68

Amount that Cindy raised
= 129 - 1 u
= 129 - 68
= $61

Answer(s): $61