Ken had 160 more erasers than Perry. Ken gave 25% of his erasers to Perry. Perry in return gave 80% of his erasers to Ken. In the end, Perry had 340 less erasers than Ken. How many erasers did Ken have at first?
| |
Ken |
Perry |
Comparing Ken
and Peter at first |
160 more |
|
| Before |
4 u + 160 |
4 u |
| Change 1 |
- 1 u - 40 |
+ 1 u + 40 |
| After 1 |
3 u + 120 |
5 u + 40 |
| Change 2 |
+ 4 u + 32 |
- 4 u - 32 |
| After 2 |
7 u + 152 |
1 u + 8 |
25% =
25100 =
1425% x 160
=
25100 x 160
= 40
80% x 40
=
80100 x 40
= 32
80% x 5 u
=
80100 x 5 u
= 4 u
Perry had 340 less erasers than Ken in the end. If another 340 erasers are given to Perry, both will have the same number of erasers.
7 u + 152 = 1 u + 8 + 340
7 u - 1 u = 8 + 340 - 152
6 u = 196
1 u = 196 ÷ 6 = 28
Number of Perry's erasers at first
= 4 u
= 4 x 28
= 112
Answer: 112
