Hilda and Gabby collected pens. Hilda gave 20% of her pens to Gabby. As a result, Gabby's pens increased by 80%. If Hilda had 64 pens left, find the total number of pens the two girls had at first.
| |
Hilda |
Gabby |
Comparing the change
in Gabby'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 Hilda gave to Gabby is repeated. Make the number of pens that Hilda gave to Gabby the same. LCM of 1 and 4 is 4.
Number of pens that Hilda had in the end = 16 u
16 u = 64
1 u = 64 ÷ 16 = 4
Number of pens that Hilda and Gabby had at first
= 20 u + 5 u
= 25 u
= 25 x 4
= 100
Answer(s): 100
