Eric and Will have some money. If Eric gives $140 to Will, the ratio of their money will be 2 : 5. If Eric gives $689 to Will, the ratio of their money will be 1: 4. How much does Eric have?
| |
Case 1 |
Case 2 |
| |
Eric |
Will |
Eric |
Will |
| Before |
10 u + $140 |
25 u - $140 |
7 u + $689 |
28 u - $689 |
| Change |
- $140 |
+ $140 |
- $689 |
+ $689 |
After
|
2x5 =
10 u |
5x5 =
25 u |
1x7 =
7 u |
4x7 =
28 u |
The total amounts in both cases remain unchanged. Make the total amounts in both cases the same. LCM of 7 and 5 is 35.
The amount that Eric has at first is the same in both cases.
10 u + 140 = 7 u + 689
10 u - 7 u = 689 - 140
3 u = 549
1 u = 549 ÷ 3 = 183
Amount that Eric has
= 10 u + 140
= 10 x 183 + 140
= 1830 + 140
= $1970
Answer(s): $1970
