Rachel had a collection of 2230 grey, brown and yellow marbles. After Rachel gave away 340 grey marbles, the number of grey marbles was 130 fewer than the number of brown marbles. Given that the number of yellow marbles was twice as many as the number of brown marbles, how many grey marbles did Rachel have at first?
| |
Grey marbles |
Brown marbles |
Yellow marbles |
Total |
| Before |
1 u + 340 |
1 u + 130 |
2 u + 260 |
2230 |
| Change |
- 340 |
|
|
|
| After |
1 u |
1 u + 130 |
2 u + 260 |
|
Number of yellow marbles in the end
= 2 x (1 u + 130)
= 2 u + 260
Total number of marbles at first
= 1 u + 340 + 1 u + 130 + 2 u + 260
= 4 u + 730
4 u + 730 = 2230
4 u = 2230 - 730
4 u = 1500
1 u = 1500 ÷ 4 = 375
Number of grey marbles that Rachel had at first
= 1 u + 340
= 375 + 340
= 715
Answer(s): 715
