Sarah and Pamela collected pens. Pamela gave 75% of her pens to Sarah. As a result, Sarah's pens increased by 40%. If Sarah had 231 pens left, find the total number of pens the two girls had at first.
| |
Comparing the change
in Pamela's pens |
Pamela |
Sarah |
| Before |
4x2 =
8 u |
|
5x3 =
15 u |
| Change |
- 3x2 =
- 6 u |
- 2x3 =
- 6 u |
+ 2x3 =
+ 6 u |
| After |
1x2 =
2 u |
|
7x3 =
21 u |
75% =
75100 =
34 40% =
40100 =
25 The number of pens that Sarah gave to Pamela is repeated. Make the number of pens that Sarah gave to Pamela the same. LCM of 2 and 3 is 6.
Number of pens that Sarah had in the end = 21 u
21 u = 231
1 u = 231 ÷ 21 = 11
Number of pens that Pamela and Sarah had at first
= 8 u + 15 u
= 23 u
= 23 x 11
= 253
Answer(s): 253
