Kathy had 55 more erasers than Anna. After Anna gave away
47 of her erasers, Kathy had four times as many erasers as Anna. How many erasers did Anna have at first?
| |
Kathy |
Anna |
Comparing Kathy and
Anna at first |
55 more |
|
| Before |
12 u |
7 u |
| Change |
|
- 4 u |
| After |
12 u |
3 u |
Comparing Kathy and
Anna in the end |
4x3 =
12 u |
1x3 =
3 u |
Number of erasers that Anna had in the end is repeated. Make the number of erasers that Anna had in the end the same. LCM of 1 and 3 is 3.
Number of erasers that Kathy had at first = 12 u
Number of erasers that Kathy had more than Anna at first
= 12 u - 7 u
= 5 u
5 u = 55
1 u = 55 ÷ 5 = 11
Number of erasers that Anna had at first
= 7 u
= 7 x 11
= 77
Answer(s): 77
