Penelope had the same number of silver, pink and black pens at first. After giving some silver and pink pens and 41 black pens away, Penelope had 205 pens left. There were 2 times as many silver pens as pink pens left. The number of black pens left was 20 fewer than the number of silver pens left. How many black pens did she have at first?
| |
Pink |
Silver |
Black |
Total |
| Before |
2 u + 21 |
2 u + 21 |
2 u + 21 |
|
| Change |
- 1 u - 21 |
- 21 |
- 41 |
|
| After |
1 u |
2 u |
2 u - 20 |
205 |
Penelope had the same number of silver, pink and black pens at first.
Total number of pens in the end
= 1 u + 2 u + 2 u - 20
= 5 u - 20
5 u - 20 = 205
5 u = 205 + 20
5 u = 225
1 u = 225 ÷ 5 = 45
Number of black pens that Penelope had at first
= 2 u - 20 + 41
= 2 u + 21
= 2 x 45 + 21
= 111
Answer(s): 111
