PSLE At a sale, Lee bought 7 cups of the same kind. His sister bought 4 such cups. She also bought 5 mugs at $3.30 each. Altogether, she spent $12.30 less than Lee. What was the total amount of money Lee and his sister spent?
|
Lee |
His sister |
Items bought
|
7 cups
|
4 cups + 5 mugs = 4 cups + 16.50 |
Comparing the amounts paid |
$12.30 more |
|
Amount that his sister spent on 5 mugs
= 5 x 3.30
= $16.50
Let the cost of 1 cup be 1 C.
If Lee spent $12.30 less, each would pay the same amount.
7 C - 12.30 = 4 C + 16.50
7 C - 4 C = 16.50 + 12.30
7 C - 4 C = 28.80
3 C = 28.80
1 C = 28.80 ÷ 3 = 9.60
Total amount that Lee and his sister spent
= 7 C + 4 C + 16.50
= 11 C + 16.50
= 11 x 9.60 + 16.50
= 105.60 + 16.50
= $122.10
Answer(s): $122.10