John had thrice as much money as Mary. After John had given Mary $158, they had an equal amount of money left. How much money did each of them have at first?
- Mary
- John
|
Mary |
John |
Before |
1 u |
3 u |
Change |
+ $158 |
- $158 |
After |
1 u + $158 |
3 u - $158 |
The amounts that John and Mary had in the end are the same.
3 u - 158 = 1 u + 158
3 u - 1 u = 158 + 158
2 u = 316
1 u = 316 ÷ 2 = 158
Amount that Mary had at first
= 1 u
= $158
Amount that John had at first
= 3 u
= 3 x 158
= $474
Answer(s): (a) $158; (b) $474