Luke had 60 more erasers than Sam. Luke gave 25% of his erasers to Sam. Sam in return gave 80% of his erasers to Luke. In the end, Luke had 112 more erasers than Sam. How many erasers did Luke have at first?
| |
Luke |
Sam |
Comparing Luke
and Peter at first |
60 more |
|
| Before |
4 u + 60 |
4 u |
| Change 1 |
- 1 u - 15 |
+ 1 u + 15 |
| After 1 |
3 u + 45 |
5 u + 15 |
| Change 2 |
+ 4 u + 12 |
- 4 u - 12 |
| After 2 |
7 u + 57 |
1 u + 3 |
25% =
25100 =
1425% x 60
=
25100 x 60
= 15
80% x 15
=
80100 x 15
= 12
80% x 5 u
=
80100 x 5 u
= 4 u
Luke had 112 more erasers than Sam in the end. If another 112 erasers are given to Sam, both will have the same number of erasers.
7 u + 57 = 1 u + 3 + 112
7 u - 1 u = 3 + 112 - 57
2 u = 58
1 u = 58 ÷ 2 = 29
Number of Luke's erasers at first
= 4 u + 60
= 4 x 29 + 60
= 116 + 60
= 176
Answer: 176
