Yen and Shannon collected pens. Yen gave 20% of her pens to Shannon. As a result, Shannon's pens increased by 80%. If Yen had 80 pens left, find the total number of pens the two girls had at first.
| |
Yen |
Shannon |
Comparing the change
in Shannon's pens |
| Before |
5x4 =
20 u |
|
5x1 =
5 u |
| Change |
- 1x4 =
- 4 u |
+ 1x4 =
+ 4 u |
+ 4x1 =
+ 4 u |
| After |
4x4 =
16 u |
|
9x1 =
9 u |
20% =
20100 =
15 80% =
80100 =
45 The number of pens that Yen gave to Shannon is repeated. Make the number of pens that Yen gave to Shannon the same. LCM of 1 and 4 is 4.
Number of pens that Yen had in the end = 16 u
16 u = 80
1 u = 80 ÷ 16 = 5
Number of pens that Yen and Shannon had at first
= 20 u + 5 u
= 25 u
= 25 x 5
= 125
Answer(s): 125
