14 of Mary's money was equal to
15 of Lucy's money at first. After Mary spent $84 and Lucy spent
13 of her money, Mary had
12 as much money as Lucy.
- How much money did Lucy have at first?
- How much money did Lucy have in the end?
| |
Mary |
Lucy |
Comparing Mary
and Lucy at first |
4x3 =
12 u |
5x3 =
15 u |
| Before |
|
3x5 =
15 u |
| Change |
- $84 |
- 1x5 =
- 5 u |
| After |
|
2x5 =
10 u |
Comparing Mary
and Lucy in the end |
1x5 =
5 u |
2x5 =
10 u |
14 Mary's money =
15 Lucy's money
Make numerators the same.
14 Mary's money =
1x15x1 Lucy's money
14 Mary's money =
15 Lucy's money
Mary's money : Lucy's money = 4 : 5
The amount that Lucy had at first is repeated. Make the amount that Lucy had at first the same. LCM of 5 and 3 is 15.
Amount that Mary spent
= 12 u - 5 u
= 7 u
7 u = 84
1 u = 84 ÷ 7 = 12
(a)
Amount that Lucy had at first
= 15 u
= 15 x 12
= $180
(b)
Amount that Lucy had in the end
= 10 u
= 10 x 12
= $120
Answer(s): (a) $180; (b) $120
