Bobby and Ben had an equal number of books. Bobby donated
15 of her books and Ben donated
13 of his books. Ben donated 18 more books than Bobby. How many books did Ben have at first?
| |
Bobby |
Ben |
Before
|
5x3 =
15 u |
3x5 =
15 u |
Change
|
- 1x3 =
- 3 u |
- 1x5 =
- 5 u |
After
|
4x3 =
12 u |
2x5 =
10 u |
The number of books that Bobby and Ben each had at first is the same. Make the number of books that Bobby and Ben had at first the same. LCM of 5 and 3 is 15.
Number of books that Ben donated more than Bobby
= 5 u - 3 u
= 2 u
2 u = 18
1 u = 18 ÷ 2 = 9
Number of books that Ben had
= 15 u
= 15 x 9
= 135
Answer(s): 135
