Harry and Eric had 78 files together. Harry had 16 more files than Eric. Both of them sold some of their files. Eric sold 20% less files than what Harry sold. In the end, Eric had half as many files left as Harry. How many files had Harry left?
| |
Harry
(1) |
Eric
(2) |
Make p the same
(2)x2 = (3) |
Comparing Harry
and Eric at first |
16 more |
|
|
| Before |
47 |
31 |
62 |
| Change |
- 5 u |
- 4 u |
- 8 u |
| After |
2 p |
1 p |
2 p |
Number of files that Eric had at first
= (78 - 16) ÷ 2
= 62 ÷ 2
= 31
Number of files that Harry had at first
= 31 + 16
= 47
Number of files that Eric sold in percent
= 100% - 20%
= 80%
80% =
80100 =
45 Make p the same.
(1) = (3)
47 - 5 u = 62 - 8 u
8 u - 5 u = 62 - 47
3 u = 15
1 u = 15 ÷ 3 = 5
Number of files that Harry had left
= 47 - 5 u
= 47 - 5 x 5
= 47 - 25
= 22
Answer(s): 22
