The ratio of the number of green coins to red coins is 7 : 5. After Asher gives away 20 green coins and buys another 90 red coins, there is equal number of green coins and red coins. How many coins does Asher have now?
| |
Green |
Red |
| Before |
7 u |
5 u |
| Change |
- 20 |
+ 90 |
| After |
7 u - 20 |
5 u + 90 |
The number of green coins and red coins in the end is the same.
7 u - 20 = 5 u + 90
7 u - 5 u = 90 + 20
2 u = 110
1 u = 110 ÷ 2 = 55
Number of coins that Asher has now
= 7 u - 20 + 5 u + 90
= 7 u + 5 u - 20 + 90
= 12 u + 70
= 12 x 55 + 70
= 660 + 70
= 730
Answer(s): 730
