Marion had 20 more erasers than Kathy. After Kathy gave away
35 of her erasers, Marion had five times as many erasers as Kathy. How many erasers did Kathy have at first?
| |
Marion |
Kathy |
Comparing Marion and
Kathy at first |
20 more |
|
| Before |
10 u |
5 u |
| Change |
|
- 3 u |
| After |
10 u |
2 u |
Comparing Marion and
Kathy in the end |
5x2 =
10 u |
1x2 =
2 u |
Number of erasers that Kathy had in the end is repeated. Make the number of erasers that Kathy had in the end the same. LCM of 1 and 2 is 2.
Number of erasers that Marion had at first = 10 u
Number of erasers that Marion had more than Kathy at first
= 10 u - 5 u
= 5 u
5 u = 20
1 u = 20 ÷ 5 = 4
Number of erasers that Kathy had at first
= 5 u
= 5 x 4
= 20
Answer(s): 20
