Kylie had a collection of 2020 grey, yellow and green balls. After Kylie gave away 290 grey balls, the number of grey balls was 220 fewer than the number of yellow balls. Given that the number of green balls was four times as many as the number of yellow balls, how many grey balls did Kylie have at first?
| |
Grey balls |
Yellow balls |
Green balls |
Total |
| Before |
1 u + 290 |
1 u + 220 |
4 u + 880 |
2020 |
| Change |
- 290 |
|
|
|
| After |
1 u |
1 u + 220 |
4 u + 880 |
|
Number of green balls in the end
= 4 x (1 u + 220)
= 4 u + 880
Total number of balls at first
= 1 u + 290 + 1 u + 220 + 4 u + 880
= 6 u + 1390
6 u + 1390 = 2020
6 u = 2020 - 1390
6 u = 630
1 u = 630 ÷ 6 = 105
Number of grey balls that Kylie had at first
= 1 u + 290
= 105 + 290
= 395
Answer(s): 395
