Zoe had the same number of silver, yellow and black pens at first. After giving some silver and yellow pens and 46 black pens away, Zoe had 246 pens left. There were 4 times as many silver pens as yellow pens left. The number of black pens left was 33 fewer than the number of silver pens left. How many black pens did she have at first?
| |
Yellow |
Silver |
Black |
Total |
| Before |
4 u + 13 |
4 u + 13 |
4 u + 13 |
|
| Change |
- 3 u - 13 |
- 13 |
- 46 |
|
| After |
1 u |
4 u |
4 u - 33 |
246 |
Zoe had the same number of silver, yellow and black pens at first.
Total number of pens in the end
= 1 u + 4 u + 4 u - 33
= 9 u - 33
9 u - 33 = 246
9 u = 246 + 33
9 u = 279
1 u = 279 ÷ 9 = 31
Number of black pens that Zoe had at first
= 4 u - 33 + 46
= 4 u + 13
= 4 x 31 + 13
= 137
Answer(s): 137
