Usha and Betty had $155. Betty had $9 more than Usha. Usha spent 4 times as much as Betty and was left with
35 as much as Betty. How much did Usha spend more than Betty?
| |
Make p the same
(1)x5 = (3) |
Usha
(1) |
Betty
(2) |
Make p the same
(2)x3 = (4) |
Total
|
Comparing Usha
and Betty at first |
|
|
$9 more |
|
$155 |
| Before |
$365 |
$73 |
$82 |
$246 |
|
| Change |
- 20 u |
- 4 u |
- 1 u |
- 3 u |
|
| After |
15 p |
3 p |
5 p |
15 p |
|
Amount that Usha had at first
= (155 - 9) ÷ 2
= 146 ÷ 2
= $73
Amount that Betty had at first
= 73 + 9
= $82
73 - 4 u = 3 p --- (1)
82 - 1 u = 5 p --- (2)
Make p the same.
(1)
x 5
365 - 20 u =
15 p --- (3)
(2)
x 3
246 - 3 u =
15 p --- (4)
(4) = (3)
246 - 3 u = 365 - 20 u
20 u - 3 u = 365 - 246
17 u = 119
1 u = 119 ÷ 17 = 7
Amount that Usha spent more than Betty
= 4 u - 1 u
= 3 u
= 3 x 7
= $21
Answer(s): $21
