The ratio of the number of green marbles to blue marbles is 9 : 4. After Henry gives away 80 green marbles and buys another 90 blue marbles, there is equal number of green marbles and blue marbles. How many marbles does Henry have now?
| |
Green |
Blue |
| Before |
9 u |
4 u |
| Change |
- 80 |
+ 90 |
| After |
9 u - 80 |
4 u + 90 |
The number of green marbles and blue marbles in the end is the same.
9 u - 80 = 4 u + 90
9 u - 4 u = 90 + 80
5 u = 170
1 u = 170 ÷ 5 = 34
Number of marbles that Henry has now
= 9 u - 80 + 4 u + 90
= 9 u + 4 u - 80 + 90
= 13 u + 10
= 13 x 34 + 10
= 442 + 10
= 452
Answer(s): 452
