Daniel and Wesley had 87 files together. Daniel had 15 more files than Wesley. Both of them sold some of their files. Wesley sold 20% less files than what Daniel sold. In the end, Wesley had half as many files left as Daniel. How many files had Daniel left?
| |
Daniel
(1) |
Wesley
(2) |
Make p the same
(2)x2 = (3) |
Comparing Daniel
and Wesley at first |
15 more |
|
|
| Before |
51 |
36 |
72 |
| Change |
- 5 u |
- 4 u |
- 8 u |
| After |
2 p |
1 p |
2 p |
Number of files that Wesley had at first
= (87 - 15) ÷ 2
= 72 ÷ 2
= 36
Number of files that Daniel had at first
= 36 + 15
= 51
Number of files that Wesley sold in percent
= 100% - 20%
= 80%
80% =
80100 =
45 Make p the same.
(1) = (3)
51 - 5 u = 72 - 8 u
8 u - 5 u = 72 - 51
3 u = 21
1 u = 21 ÷ 3 = 7
Number of files that Daniel had left
= 51 - 5 u
= 51 - 5 x 7
= 51 - 35
= 16
Answer(s): 16
