The ratio of the number of green pens to red pens is 5 : 3. After Japheth gives away 20 green pens and buys another 30 red pens, there is equal number of green pens and red pens. How many pens does Japheth have now?
| |
Green |
Red |
| Before |
5 u |
3 u |
| Change |
- 20 |
+ 30 |
| After |
5 u - 20 |
3 u + 30 |
The number of green pens and red pens in the end is the same.
5 u - 20 = 3 u + 30
5 u - 3 u = 30 + 20
2 u = 50
1 u = 50 ÷ 2 = 25
Number of pens that Japheth has now
= 5 u - 20 + 3 u + 30
= 5 u + 3 u - 20 + 30
= 8 u + 10
= 8 x 25 + 10
= 200 + 10
= 210
Answer(s): 210
