Shannon had a collection of 1520 white, black and purple balls. After Shannon gave away 290 white balls, the number of white balls was 240 fewer than the number of black balls. Given that the number of purple balls was thrice as many as the number of black balls, how many white balls did Shannon have at first?
| |
White balls |
Black balls |
Purple balls |
Total |
| Before |
1 u + 290 |
1 u + 240 |
3 u + 720 |
1520 |
| Change |
- 290 |
|
|
|
| After |
1 u |
1 u + 240 |
3 u + 720 |
|
Number of purple balls in the end
= 3 x (1 u + 240)
= 3 u + 720
Total number of balls at first
= 1 u + 290 + 1 u + 240 + 3 u + 720
= 5 u + 1250
5 u + 1250 = 1520
5 u = 1520 - 1250
5 u = 270
1 u = 270 ÷ 5 = 54
Number of white balls that Shannon had at first
= 1 u + 290
= 54 + 290
= 344
Answer(s): 344
