Bobby and Oliver had 69 files together. Oliver had 3 less files than Bobby. Both of them sold some of their files. Oliver sold 25% more files than what Bobby sold. In the end, Oliver had half as many files left as Bobby. How many files had Oliver left?
| |
Bobby
(1) |
Oliver
(2) |
Make p the same
(2)x2 = (3) |
Comparing Bobby
and Oliver at first |
3 more |
|
|
| Before |
36 |
33 |
66 |
| Change |
- 4 u |
- 5 u |
- 10 u |
| After |
2 p |
1 p |
2 p |
Number of files that Oliver had at first
= (69 - 3) ÷ 2
= 66 ÷ 2
= 33
Number of files that Bobby had at first
= 33 + 3
= 36
Number of files that Oliver sold in percent
= 100% + 25%
= 125%
125% =
125100 =
54 Make p the same.
(1) = (3)
36 - 4 u = 66 - 10 u
10 u - 4 u = 66 - 36
6 u = 30
1 u = 30 ÷ 6 = 5
Number of files that Oliver had left
= 33 - 5 u
= 33 - 5 x 5
= 33 - 25
= 8
Answer(s): 8
