John had 90 more erasers than Will. John gave 20% of his erasers to Will. Will in return gave 50% of his erasers to John. In the end, John had 246 more erasers than Will. How many erasers did John have at first?
| |
John |
Will |
Comparing John
and Peter at first |
90 more |
|
| Before |
5 u + 90 |
5 u |
| Change 1 |
- 1 u - 18 |
+ 1 u + 18 |
| After 1 |
4 u + 72 |
6 u + 18 |
| Change 2 |
+ 3 u + 9 |
- 3 u - 9 |
| After 2 |
7 u + 81 |
3 u + 9 |
20% =
20100 =
1520% x 90
=
20100 x 90
= 18
50% x 18
=
50100 x 18
= 9
50% x 6 u
=
50100 x 6 u
= 3 u
John had 246 more erasers than Will in the end. If another 246 erasers are given to Will, both will have the same number of erasers.
7 u + 81 = 3 u + 9 + 246
7 u - 3 u = 9 + 246 - 81
6 u = 174
1 u = 174 ÷ 6 = 29
Number of John's erasers at first
= 5 u + 90
= 5 x 29 + 90
= 145 + 90
= 235
Answer: 235
