Gabby and Cindy collected pens. Gabby gave 20% of her pens to Cindy. As a result, Cindy's pens increased by 75%. If Gabby had 108 pens left, find the total number of pens the two girls had at first.
| |
Gabby |
Cindy |
Comparing the change
in Cindy's pens |
| Before |
5x3 =
15 u |
|
4x1 =
4 u |
| Change |
- 1x3 =
- 3 u |
+ 1x3 =
+ 3 u |
+ 3x1 =
+ 3 u |
| After |
4x3 =
12 u |
|
7x1 =
7 u |
20% =
20100 =
15 75% =
75100 =
34 The number of pens that Gabby gave to Cindy is repeated. Make the number of pens that Gabby gave to Cindy the same. LCM of 1 and 3 is 3.
Number of pens that Gabby had in the end = 12 u
12 u = 108
1 u = 108 ÷ 12 = 9
Number of pens that Gabby and Cindy had at first
= 15 u + 4 u
= 19 u
= 19 x 9
= 171
Answer(s): 171
