Sarah and Opal collected cards. Opal gave 60% of her cards to Sarah. As a result, Sarah's cards increased by 20%. If Sarah had 108 cards left, find the total number of cards the two girls had at first.
| |
Comparing the change
in Opal's cards |
Opal |
Sarah |
| Before |
5x1 =
5 u |
|
5x3 =
15 u |
| Change |
- 3x1 =
- 3 u |
- 1x3 =
- 3 u |
+ 1x3 =
+ 3 u |
| After |
2x1 =
2 u |
|
6x3 =
18 u |
60% =
60100 =
35 20% =
20100 =
15 The number of cards that Sarah gave to Opal is repeated. Make the number of cards that Sarah gave to Opal the same. LCM of 1 and 3 is 3.
Number of cards that Sarah had in the end = 18 u
18 u = 108
1 u = 108 ÷ 18 = 6
Number of cards that Opal and Sarah had at first
= 5 u + 15 u
= 20 u
= 20 x 6
= 120
Answer(s): 120
