Jean had a collection of 1680 brown, white and gold marbles. After Jean gave away 330 brown marbles, the number of brown marbles was 240 fewer than the number of white marbles. Given that the number of gold marbles was thrice as many as the number of white marbles, how many brown marbles did Jean have at first?
| |
Brown marbles |
White marbles |
Gold marbles |
Total |
| Before |
1 u + 330 |
1 u + 240 |
3 u + 720 |
1680 |
| Change |
- 330 |
|
|
|
| After |
1 u |
1 u + 240 |
3 u + 720 |
|
Number of gold marbles in the end
= 3 x (1 u + 240)
= 3 u + 720
Total number of marbles at first
= 1 u + 330 + 1 u + 240 + 3 u + 720
= 5 u + 1290
5 u + 1290 = 1680
5 u = 1680 - 1290
5 u = 390
1 u = 390 ÷ 5 = 78
Number of brown marbles that Jean had at first
= 1 u + 330
= 78 + 330
= 408
Answer(s): 408
