The ratio of the number of blue marbles to green marbles is 5 : 3. After Jeremy gives away 60 blue marbles and buys another 70 green marbles, there is equal number of blue marbles and green marbles. How many marbles does Jeremy have now?
| |
Blue |
Green |
| Before |
5 u |
3 u |
| Change |
- 60 |
+ 70 |
| After |
5 u - 60 |
3 u + 70 |
The number of blue marbles and green marbles in the end is the same.
5 u - 60 = 3 u + 70
5 u - 3 u = 70 + 60
2 u = 130
1 u = 130 ÷ 2 = 65
Number of marbles that Jeremy has now
= 5 u - 60 + 3 u + 70
= 5 u + 3 u - 60 + 70
= 8 u + 10
= 8 x 65 + 10
= 520 + 10
= 530
Answer(s): 530
