Barbara had the same number of blue, pink and black erasers at first. After giving some blue and pink erasers and 57 black erasers away, Barbara had 185 erasers left. There were 2 times as many blue erasers as pink erasers left. The number of black erasers left was 45 fewer than the number of blue erasers left. How many black erasers did she have at first?
| |
Pink |
Blue |
Black |
Total |
| Before |
2 u + 12 |
2 u + 12 |
2 u + 12 |
|
| Change |
- 1 u - 12 |
- 12 |
- 57 |
|
| After |
1 u |
2 u |
2 u - 45 |
185 |
Barbara had the same number of blue, pink and black erasers at first.
Total number of erasers in the end
= 1 u + 2 u + 2 u - 45
= 5 u - 45
5 u - 45 = 185
5 u = 185 + 45
5 u = 230
1 u = 230 ÷ 5 = 46
Number of black erasers that Barbara had at first
= 2 u - 45 + 57
= 2 u + 12
= 2 x 46 + 12
= 104
Answer(s): 104
