Rachel had 120 pens.
45 of them were blue pens and the rest were purple pens. After she had given away some blue pens, the ratio of the number of blue pens to the number of purple pens became 3 : 4. How many pens did she have in the end?
| |
Blue |
Purple |
Total |
| Before |
4x4 =
16 u |
1x4 =
4 u |
5x4 =
20 u |
| Change |
- 13 u |
|
|
| After |
3 u |
4 u |
7 u |
The number of purple pens remained unchanged.
LCM of 1 and 4 = 4
Total number of pens at first = 20 u
20 u = 120
1 u = 120 ÷ 20 = 6
Number of pens that Rachel had in the end
= 3 u + 4 u
= 7 u
= 7 x 6
= 42
Answer(s):42
