Betty had 150 pens.
23 of them were purple pens and the rest were pink pens. After she had given away some purple pens, the ratio of the number of purple pens to the number of pink pens became 3 : 5. How many purple pens did she give away?
| |
Purple |
Pink |
Total |
| Before |
2x5 =
10 u |
1x5 =
5 u |
3x5 =
15 u |
| Change |
- 7 u |
|
|
| After |
3 u |
5 u |
8 u |
The number of pink pens remained unchanged.
LCM of 1 and 5 = 5
Total number of pens at first = 15 u
15 u = 150
1 u = 150 ÷ 15 = 10
Number of purple pens that she gave away
= 10 u - 3 u
= 7 u
= 7 x 10
= 70
Answer(s):70
