Tina and Barbara had $159. Barbara had $31 more than Tina. Tina spent 3 times as much as Barbara and was left with
25 as much as Barbara. How much did Barbara spend less than Tina?
| |
Make p the same
(1) x 5 = (3) |
Tina
(1) |
Barbara
(2) |
Make p the same
(2) x 2 = (4) |
Total
|
Comparing Tina
and Barbara at first |
|
|
$31 more |
|
$159 |
| Before |
$320 |
$64 |
$95 |
$190 |
|
| Change |
- 15 u |
- 3 u |
- 1 u |
- 2 u |
|
| After |
10 p |
2 p |
5 p |
10 p |
|
Amount that Tina had at first
= (159 - 31) ÷ 2
= 128 ÷ 2
= $64
Amount that Barbara had at first
= 64 + 31
= $95
64 - 3 u = 2 p --- (1)
95 - 1 u = 5 p --- (2)
Make p the same.
(1)
x 5
320 - 15 u =
10 p --- (3)
(2)
x 2
190 - 2 u =
10 p --- (4)
(4) = (3)
190 - 2 u = 320 - 15 u
15 u - 2 u = 320 - 190
13 u = 130
1 u = 130 ÷ 13 = 10
Amount that Barbara spent less than Tina
= 3 u - 1 u
= 2 u
= 2 x 10
= $20
Answer(s): $20
