Cathy and Rachel had an equal number of erasers at first. Cathy used
15 of her erasers and Rachel used
18 of her erasers. They used 52 erasers altogether. How many erasers did Rachel have in the end?
| |
Cathy |
Rachel |
| Before |
5x8 =
40 u |
8x5 =
40 u |
| Change |
- 1x8 =
- 8 u |
- 1x5 =
- 5 u |
| After |
4x8 =
32 u |
7x5 =
35 u |
The number of erasers that Cathy and Rachel each had at first is the same. Make the number of erasers that Cathy and Rachel each had at first the same. LCM of 5 and 8 is 40.
Number of erasers that Cathy and Rachel used
= 8 u + 5 u
= 13 u
13 u = 52
1 u = 52 ÷ 13 = 4
Number of erasers that Rachel had in the end
= 35 u
= 35 x 4
= 140
Answer(s): 140
