Luke and Carl had 103 files together. Luke had 13 more files than Carl. Both of them sold some of their files. Carl sold 10% less files than what Luke sold. In the end, Carl had half as many files left as Luke. How many files had Luke left?
| |
Luke
(1) |
Carl
(2) |
Make p the same
(2)x2 = (3) |
Comparing Luke
and Carl at first |
13 more |
|
|
| Before |
58 |
45 |
90 |
| Change |
- 10 u |
- 9 u |
- 18 u |
| After |
2 p |
1 p |
2 p |
Number of files that Carl had at first
= (103 - 13) ÷ 2
= 90 ÷ 2
= 45
Number of files that Luke had at first
= 45 + 13
= 58
Number of files that Carl sold in percent
= 100% - 10%
= 90%
90% =
90100 =
910 Make p the same.
(1) = (3)
58 - 10 u = 90 - 18 u
18 u - 10 u = 90 - 58
8 u = 32
1 u = 32 ÷ 8 = 4
Number of files that Luke had left
= 58 - 10 u
= 58 - 10 x 4
= 58 - 40
= 18
Answer(s): 18
