Rachel had 120 pens.
78 of them were red pens and the rest were green pens. After she had given away some red pens, the ratio of the number of red pens to the number of green pens became 3 : 5. How many red pens did she give away?
| |
Red |
Green |
Total |
| Before |
7x5 =
35 u |
1x5 =
5 u |
8x5 =
40 u |
| Change |
- 32 u |
|
|
| After |
3 u |
5 u |
8 u |
The number of green pens remained unchanged.
LCM of 1 and 5 = 5
Total number of pens at first = 40 u
40 u = 120
1 u = 120 ÷ 40 = 3
Number of red pens that she gave away
= 35 u - 3 u
= 32 u
= 32 x 3
= 96
Answer(s):96
