Mr Lin had $643 more than Mr Lau at first. After Mr Lau had spent $389, Mr Lin had 4 times as much money as Mr Lau. Find the amount of money Mr Lau had at first.
| |
Mr Lau |
Mr Lin
|
| Comparing Mr Lau and Mr Lin at first |
|
$643 more |
| Before |
1 u + $389 |
4 u |
| Change |
- $389 |
|
| After |
1 u |
4 u |
After
Amount that Mr Lau has = 1 u
Amount that Mr Lin has = 4 x 1 u = 4 u
Before
Amount that Mr Lau has = 1 u + 389
Amount that Mr Lin has = 4 u
Mr Lin had $643 more than Mr Lau at first.
If another $643 is given to Mr Lau at first, both will have the same amount at first.
4 u = 1 u + 389 + 643
4 u = 1 u + 1032
4 u - 1 u = 1032
3 u = 1032
1 u = 1032 ÷ 3 = 344
Amount that Mr Lau had at first
= 1 u + 389
= 344 + 389
= $733
Answer(s): $733
