The ratio of the amount of money that Mary and Dana brought along was 4 : 5. For their brother's present, Mary and Dana shared the cost in the ratio of 3 : 2. Mary used up
35 of her money to pay for her share. After paying for her share, Dana had $136 left. How much was the present?
| |
Mary |
Dana |
| Before |
4 u |
5 u |
| Change |
- 2.4 u |
- 1.6 u |
Comparing the cost shared
between Mary and Dana |
- 3 p =
- 2.4 u |
- 2 p =
- 1.6 u |
| After |
1.6 u |
136 |
Amount that Mary spent on the present
=
35 x 4 u
= 2.4 u
3 p = 2.4 u
1 p = 2.4 u ÷ 3 = 0.8
2 p = 2 x 0.8 = 1.6 u
Amount that Dana had left
= 5 u - 1.6 u
= 3.4 u
3.4 u = 136
1 u = 136 ÷ 3.4 = 40
Cost of the present
= 2.4 u + 1.6 u
= 4 u
= 4 x 40
= $160
Answer: $160
