Irene and Mary went shopping with a total of $840. After Irene spent
45 of her money and Mary spent $21, the ratio of Mary's money became 4 times as much as Irene's money. Find the ratio of Irene's money to Mary's money at first.
| |
Irene |
Mary |
| Before |
5 u |
4 u + 21 |
| Change |
- 4 u |
- 21 |
| After |
1 u |
|
| Comparing between Irene and Mary in the end |
1 u |
4 u |
Total amount that Irene and Mary had at first
= 5 u + 4 u + 21
= 9 u + 21
9 u + 21 = 840
5 u + 4 u = 840 - 21
9 u = 819
1 u = 819 ÷ 9 = 91
Amount that Irene had at first
= 5 u
= 5 x 91
= $455
Amount that Mary had at first
= 840 - 455
= $385
At first
Irene : Mary
455 : 385
13 : 11
Answer(s): 13 : 11
