Ivory and Cindy collected pens. Cindy gave 80% of her pens to Ivory. As a result, Ivory's pens increased by 25%. If Ivory had 220 pens left, find the total number of pens the two girls had at first.
| |
Comparing the change
in Cindy's pens |
Cindy |
Ivory |
| Before |
5x1 =
5 u |
|
4x4 =
16 u |
| Change |
- 4x1 =
- 4 u |
- 1x4 =
- 4 u |
+ 1x4 =
+ 4 u |
| After |
1x1 =
1 u |
|
5x4 =
20 u |
80% =
80100 =
45 25% =
25100 =
14 The number of pens that Ivory gave to Cindy is repeated. Make the number of pens that Ivory gave to Cindy the same. LCM of 1 and 4 is 4.
Number of pens that Ivory had in the end = 20 u
20 u = 220
1 u = 220 ÷ 20 = 11
Number of pens that Cindy and Ivory had at first
= 5 u + 16 u
= 21 u
= 21 x 11
= 231
Answer(s): 231
