Sarah had 30 more erasers than Cindy. After Cindy gave away
14 of her erasers, Sarah had thrice as many erasers as Cindy. How many erasers did Cindy have at first?
| |
Sarah |
Cindy |
Comparing Sarah and
Cindy at first |
30 more |
|
| Before |
9 u |
4 u |
| Change |
|
- 1 u |
| After |
9 u |
3 u |
Comparing Sarah and
Cindy in the end |
3x3 =
9 u |
1x3 =
3 u |
Number of erasers that Cindy had in the end is repeated. Make the number of erasers that Cindy had in the end the same. LCM of 1 and 3 is 3.
Number of erasers that Sarah had at first = 9 u
Number of erasers that Sarah had more than Cindy at first
= 9 u - 4 u
= 5 u
5 u = 30
1 u = 30 ÷ 5 = 6
Number of erasers that Cindy had at first
= 4 u
= 4 x 6
= 24
Answer(s): 24
