PSLE
Four girls, Emily, Tammy, Shiyun and Gwen raised money for a charity. Emily and Tammy raised a total of $151. Together, Tammy, Shiyun and Gwen raised a total of $227. The total amount of money raised by all 4 girls is 5 times the amount that Tammy raised. How much money did Shiyun and Gwen raise?
Amount that Tammy and Emily raised = $151
Amount that Tammy, Shiyun and Gwen raised = $227

Tammy is the repeated identity.

Tammy + Emily = 151 --- (1)
Tammy + Shiyun + Gwen = 227 --- (2)

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

(1) + (2)
(Tammy + Emily) + (Tammy + Shiyun + Gwen) = 151 + 227
Tammy + 4 girls = 378
1 u + 5 u = 378
6 u = 378

1 u = 378 ÷ 6 = 63

Total amount that Shiyun and Gwen raised
= 227 - 1 u
= 227 - 63
= $164

Answer(s): $164