PSLE
Four girls, Barbara, Tammy, Usha and Wendy raised money for a charity. Barbara and Tammy raised a total of $97. Together, Tammy, Usha and Wendy raised a total of $258. The total amount of money raised by all 4 girls is 4 times the amount that Tammy raised. How much money did Usha and Wendy raise?
Amount that Tammy and Barbara raised = $97
Amount that Tammy, Usha and Wendy raised = $258

Tammy is the repeated identity.

Tammy + Barbara = 97 --- (1)
Tammy + Usha + Wendy = 258 --- (2)

Amount that Tammy raised = 1 u
Amount that 4 girls raised = 4 u

(1) + (2)
(Tammy + Barbara) + (Tammy + Usha + Wendy) = 97 + 258
Tammy + 4 girls = 355
1 u + 4 u = 355
5 u = 355

1 u = 355 ÷ 5 = 71

Total amount that Usha and Wendy raised
= 258 - 1 u
= 258 - 71
= $187

Answer(s): $187