Sarah had 90 more erasers than Xandra. After Xandra gave away
25 of her erasers, Sarah had five times as many erasers as Xandra. How many erasers did Xandra have at first?
| |
Sarah |
Xandra |
Comparing Sarah and
Xandra at first |
90 more |
|
| Before |
15 u |
5 u |
| Change |
|
- 2 u |
| After |
15 u |
3 u |
Comparing Sarah and
Xandra in the end |
5x3 =
15 u |
1x3 =
3 u |
Number of erasers that Xandra had in the end is repeated. Make the number of erasers that Xandra had in the end the same. LCM of 1 and 3 is 3.
Number of erasers that Sarah had at first = 15 u
Number of erasers that Sarah had more than Xandra at first
= 15 u - 5 u
= 10 u
10 u = 90
1 u = 90 ÷ 10 = 9
Number of erasers that Xandra had at first
= 5 u
= 5 x 9
= 45
Answer(s): 45
