Cindy had 135 pens.
23 of them were silver pens and the rest were blue pens. After she had given away some silver pens, the ratio of the number of silver pens to the number of blue pens became 3 : 5. How many silver pens did she give away?
| |
Silver |
Blue |
Total |
| Before |
2x5 =
10 u |
1x5 =
5 u |
3x5 =
15 u |
| Change |
- 7 u |
|
|
| After |
3 u |
5 u |
8 u |
The number of blue pens remained unchanged.
LCM of 1 and 5 = 5
Total number of pens at first = 15 u
15 u = 135
1 u = 135 ÷ 15 = 9
Number of silver pens that she gave away
= 10 u - 3 u
= 7 u
= 7 x 9
= 63
Answer(s):63
