PSLE
Four girls, Cathy, Pamela, Fanny and Mary raised money for a charity. Cathy and Pamela raised a total of $151. Together, Pamela, Fanny and Mary raised a total of $407. The total amount of money raised by all 4 girls is 5 times the amount that Pamela raised. How much money did Cathy raise?
Amount that Pamela and Cathy raised = $151
Amount that Pamela, Fanny and Mary raised = $407

Pamela is the repeated identity.

Pamela + Cathy = 151 --- (1)
Pamela + Fanny + Mary = 407 --- (2)

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

(1) + (2)
(Pamela + Cathy) + (Pamela + Fanny + Mary) = 151 + 407
Pamela + 4 girls = 558
1 u + 5 u = 558
6 u = 558

1 u = 558 ÷ 6 = 93

Amount that Cathy raised
= 151 - 1 u
= 151 - 93
= $58

Answer(s): $58