The ratio of Ethan's money to Oscar's money is 3 : 7. If Oscar has $21, how much must he give to Ethan so both will have the equal amount of money?
| |
Ethan |
Oscar |
Total |
| Before |
3 u |
7 u |
10 u |
| Change |
+ 2 u |
- 2 u |
|
| After |
5 u |
5 u |
10 u |
Comparing Ethan and
Oscar in the end |
1 |
1 |
|
Amount that Oscar has at first = 7 u
7 u = 21
1 u = 21 ÷ 7 = 3
Total amount that Oscar and Ethan have
= 3 u + 7 u
= 10 u
Amount that each of them will have in the end
= 10 u ÷ 2
= 5 u
Amount that Oscar must give to Ethan
= 5 u - 3 u
= 2 u
= 2 x 3
= $6
Answer(s): $6
