PSLE At a sale, Bobby bought 11 cups of the same kind. His cousin bought 8 such cups. She also bought 4 glasses at $7.80 each. Altogether, she spent $13.80 more than Bobby. What was the total amount of money Bobby and his cousin spent?
|
Bobby |
His cousin |
Items bought
|
11 cups
|
8 cups + 4 glasses = 8 cups + 31.20 |
Comparing the amounts paid |
|
$13.80 more |
Amount that his cousin spent on 4 glasses
= 4 x 7.80
= $31.20
Let the cost of 1 cup be 1 C.
If Bobby's cousin spent $13.80 less, each would pay the same amount.
11 C + 13.80 = 8 C + 31.20 - 13.80
11 C - 8 C = 31.20 - 13.80
3 C = 17.40
1 C = 17.40 ÷ 3 = 5.80
Total amount that Bobby and his cousin spent
= 11 C + 8 C + 31.20
= 19 C + 31.20
= 19 x 5.80 + 31.20
= 110.20 + 31.20
= $141.40
Answer(s): $141.40