The ratio of the number of green marbles to red marbles is 9 : 4. After Julian gives away 30 green marbles and buys another 50 red marbles, there is equal number of green marbles and red marbles. How many marbles does Julian have now?
| |
Green |
Red |
| Before |
9 u |
4 u |
| Change |
- 30 |
+ 50 |
| After |
9 u - 30 |
4 u + 50 |
The number of green marbles and red marbles in the end is the same.
9 u - 30 = 4 u + 50
9 u - 4 u = 50 + 30
5 u = 80
1 u = 80 ÷ 5 = 16
Number of marbles that Julian has now
= 9 u - 30 + 4 u + 50
= 9 u + 4 u - 30 + 50
= 13 u + 20
= 13 x 16 + 20
= 208 + 20
= 228
Answer(s): 228
