The ratio of the number of green coins to red coins is 9 : 4. After Howard gives away 40 green coins and buys another 90 red coins, there is equal number of green coins and red coins. How many coins does Howard have now?
|
Green |
Red |
Before |
9 u |
4 u |
Change |
- 40 |
+ 90 |
After |
9 u - 40 |
4 u + 90 |
The number of green coins and red coins in the end is the same.
9 u - 40 = 4 u + 90
9 u - 4 u = 90 + 40
5 u = 130
1 u = 130 ÷ 5 = 26
Number of coins that Howard has now
= 9 u - 40 + 4 u + 90
= 9 u + 4 u - 40 + 90
= 13 u + 50
= 13 x 26 + 50
= 338 + 50
= 388
Answer(s): 388