Liam and Ethan had an equal number of books. Liam donated
17 of her books and Ethan donated
13 of his books. Ethan donated 20 more books than Liam. How many books did Ethan have at first?
| |
Liam |
Ethan |
Before
|
7x3 =
21 u |
3x7 =
21 u |
Change
|
- 1x3 =
- 3 u |
- 1x7 =
- 7 u |
After
|
6x3 =
18 u |
2x7 =
14 u |
The number of books that Liam and Ethan each had at first is the same. Make the number of books that Liam and Ethan had at first the same. LCM of 7 and 3 is 21.
Number of books that Ethan donated more than Liam
= 7 u - 3 u
= 4 u
4 u = 20
1 u = 20 ÷ 4 = 5
Number of books that Ethan had
= 21 u
= 21 x 5
= 105
Answer(s): 105
