The ratio of John's money to Justin's money is 3 : 7. If Justin has $70, how much must he give to John so both will have the equal amount of money?
| |
John |
Justin |
Total |
| Before |
3 u |
7 u |
10 u |
| Change |
+ 2 u |
- 2 u |
|
| After |
5 u |
5 u |
10 u |
Comparing John and
Justin in the end |
1 |
1 |
|
Amount that Justin has at first = 7 u
7 u = 70
1 u = 70 ÷ 7 = 10
Total amount that Justin and John have
= 3 u + 7 u
= 10 u
Amount that each of them will have in the end
= 10 u ÷ 2
= 5 u
Amount that Justin must give to John
= 5 u - 3 u
= 2 u
= 2 x 10
= $20
Answer(s): $20
