PSLE
Four girls, Jean, Opal, Elyse and Emily raised money for a charity. Jean and Opal raised a total of $118. Together, Opal, Elyse and Emily raised a total of $404. The total amount of money raised by all 4 girls is 5 times the amount that Opal raised. How much money did Jean raise?
Amount that Opal and Jean raised = $118
Amount that Opal, Elyse and Emily raised = $404

Opal is the repeated identity.

Opal + Jean = 118 --- (1)
Opal + Elyse + Emily = 404 --- (2)

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

(1) + (2)
(Opal + Jean) + (Opal + Elyse + Emily) = 118 + 404
Opal + 4 girls = 522
1 u + 5 u = 522
6 u = 522

1 u = 522 ÷ 6 = 87

Amount that Jean raised
= 118 - 1 u
= 118 - 87
= $31

Answer(s): $31