At first, Christopher had
25 as many erasers as Rebecca. After Christopher bought another 20 erasers and Rebecca lost 7 erasers, Christopher had
47 as many erasers as Rebecca. Find the number of erasers Rebecca had at first.
Make p the same.
(1) x 7 = (3) |
Christopher
(1) |
Rebecca
(2) |
Make p the same
(2) x 4 = (4) |
| 14 u |
2 u |
5 u |
20 u |
| + 140 |
+ 20 |
- 7 |
- 28 |
| 28 p |
4 p |
7 p |
28 p |
Make p the same.
(4) = (3)
20 u - 28 = 14 u + 140
20 u - 14 u = 140 + 28
6 u = 168
1 u = 168 ÷ 6 = 28
Number of erasers that Rebecca had at first
= 5 u
= 5 x 28
= 140
Answer(s): 140
