Min had 4 more erasers than Barbara. After Barbara gave away
47 of her erasers, Min had thrice as many erasers as Barbara. How many erasers did Barbara have at first?
| |
Min |
Barbara |
Comparing Min and
Barbara at first |
4 more |
|
| Before |
9 u |
7 u |
| Change |
|
- 4 u |
| After |
9 u |
3 u |
Comparing Min and
Barbara in the end |
3x3 =
9 u |
1x3 =
3 u |
Number of erasers that Barbara had in the end is repeated. Make the number of erasers that Barbara had in the end the same. LCM of 1 and 3 is 3.
Number of erasers that Min had at first = 9 u
Number of erasers that Min had more than Barbara at first
= 9 u - 7 u
= 2 u
2 u = 4
1 u = 4 ÷ 2 = 2
Number of erasers that Barbara had at first
= 7 u
= 7 x 2
= 14
Answer(s): 14
