PSLE At a sale, Sean bought 11 wine glasses of the same kind. His sister bought 7 such wine glasses. She also bought 3 glasses at $2.40 each. Altogether, she spent $23.60 less than Sean. What was the total amount of money Sean and his sister spent?
|
Sean |
His sister |
Items bought
|
11 wine glasses
|
7 wine glasses + 3 glasses = 7 wine glasses + 7.20 |
Comparing the amounts paid |
$23.60 more |
|
Amount that his sister spent on 3 glasses
= 3 x 2.40
= $7.20
Let the cost of 1 wine glass be 1 W.
If Sean spent $23.60 less, each would pay the same amount.
11 W - 23.60 = 7 W + 7.20
11 W - 7 W = 7.20 + 23.60
11 W - 7 W = 30.80
4 W = 30.80
1 W = 30.80 ÷ 4 = 7.70
Total amount that Sean and his sister spent
= 11 W + 7 W + 7.20
= 18 W + 7.20
= 18 x 7.70 + 7.20
= 138.60 + 7.20
= $145.80
Answer(s): $145.80