Kimberly had a collection of 2010 brown, grey and red marbles. After Kimberly gave away 350 brown marbles, the number of brown marbles was 230 fewer than the number of grey marbles. Given that the number of red marbles was five times as many as the number of grey marbles, how many brown marbles did Kimberly have at first?
| |
Brown marbles |
Grey marbles |
Red marbles |
Total |
| Before |
1 u + 350 |
1 u + 230 |
5 u + 1150 |
2010 |
| Change |
- 350 |
|
|
|
| After |
1 u |
1 u + 230 |
5 u + 1150 |
|
Number of red marbles in the end
= 5 x (1 u + 230)
= 5 u + 1150
Total number of marbles at first
= 1 u + 350 + 1 u + 230 + 5 u + 1150
= 7 u + 1730
7 u + 1730 = 2010
7 u = 2010 - 1730
7 u = 280
1 u = 280 ÷ 7 = 40
Number of brown marbles that Kimberly had at first
= 1 u + 350
= 40 + 350
= 390
Answer(s): 390
