Julie had a collection of 2040 yellow, green and red marbles. After Julie gave away 300 yellow marbles, the number of yellow marbles was 120 fewer than the number of green marbles. Given that the number of red marbles was four times as many as the number of green marbles, how many yellow marbles did Julie have at first?
| |
Yellow marbles |
Green marbles |
Red marbles |
Total |
| Before |
1 u + 300 |
1 u + 120 |
4 u + 480 |
2040 |
| Change |
- 300 |
|
|
|
| After |
1 u |
1 u + 120 |
4 u + 480 |
|
Number of red marbles in the end
= 4 x (1 u + 120)
= 4 u + 480
Total number of marbles at first
= 1 u + 300 + 1 u + 120 + 4 u + 480
= 6 u + 900
6 u + 900 = 2040
6 u = 2040 - 900
6 u = 1140
1 u = 1140 ÷ 6 = 190
Number of yellow marbles that Julie had at first
= 1 u + 300
= 190 + 300
= 490
Answer(s): 490
