Fiona had a collection of 1700 green, grey and yellow balls. After Fiona gave away 220 green balls, the number of green balls was 120 fewer than the number of grey balls. Given that the number of yellow balls was twice as many as the number of grey balls, how many green balls did Fiona have at first?
| |
Green balls |
Grey balls |
Yellow balls |
Total |
| Before |
1 u + 220 |
1 u + 120 |
2 u + 240 |
1700 |
| Change |
- 220 |
|
|
|
| After |
1 u |
1 u + 120 |
2 u + 240 |
|
Number of yellow balls in the end
= 2 x (1 u + 120)
= 2 u + 240
Total number of balls at first
= 1 u + 220 + 1 u + 120 + 2 u + 240
= 4 u + 580
4 u + 580 = 1700
4 u = 1700 - 580
4 u = 1120
1 u = 1120 ÷ 4 = 280
Number of green balls that Fiona had at first
= 1 u + 220
= 280 + 220
= 500
Answer(s): 500
