Wendy and Olivia had an equal number of erasers at first. Wendy used
13 of her erasers and Olivia used
17 of her erasers. They used 50 erasers altogether. How many erasers did Olivia have in the end?
| |
Wendy |
Olivia |
| Before |
3x7 =
21 u |
7x3 =
21 u |
| Change |
- 1x7 =
- 7 u |
- 1x3 =
- 3 u |
| After |
2x7 =
14 u |
6x3 =
18 u |
The number of erasers that Wendy and Olivia each had at first is the same. Make the number of erasers that Wendy and Olivia each had at first the same. LCM of 3 and 7 is 21.
Number of erasers that Wendy and Olivia used
= 7 u + 3 u
= 10 u
10 u = 50
1 u = 50 ÷ 10 = 5
Number of erasers that Olivia had in the end
= 18 u
= 18 x 5
= 90
Answer(s): 90
