Tiffany and Zara had $152. Zara had $28 more than Tiffany. Tiffany spent 3 times as much as Zara and was left with
25 as much as Zara. How much did Tiffany spend?
| |
Make p the same
(1)x5 = (3) |
Tiffany
(1) |
Zara
(2) |
Make p the same
(2)x2 = (4) |
Total
|
Comparing Tiffany
and Zara at first |
|
|
$28 more |
|
$152 |
| Before |
$310 |
$62 |
$90 |
$180 |
|
| Change |
- 15 u |
- 3 u |
- 1 u |
- 2 u |
|
| After |
10 p |
2 p |
5 p |
10 p |
|
Amount that Tiffany had at first
= (152 - 28) ÷ 2
= 124 ÷ 2
= $62
Amount that Zara had at first
= 62 + 28
= $90
62 - 3 u = 2 p --- (1)
90 - 1 u = 5 p --- (2)
Make p the same.
(1)
x 5
310 - 15 u =
10 p --- (3)
(2)
x 2
180 - 2 u =
10 p --- (4)
(4) = (3)
180 - 2 u = 310 - 15 u
15 u - 2 u = 310 - 180
13 u = 130
1 u = 130 ÷ 13 = 10
Amount that Tiffany spent
= 3 u
= 3 x 10
= $30
Answer(s): $30
