Peter had 100 more coins than Tommy. Peter gave 25% of his coins to Tommy. Tommy in return gave 80% of his coins to Peter. In the end, Tommy had 190 less coins than Peter. How many coins did Peter have at first?
| |
Peter |
Tommy |
Comparing Peter
and Peter at first |
100 more |
|
| Before |
4 u + 100 |
4 u |
| Change 1 |
- 1 u - 25 |
+ 1 u + 25 |
| After 1 |
3 u + 75 |
5 u + 25 |
| Change 2 |
+ 4 u + 20 |
- 4 u - 20 |
| After 2 |
7 u + 95 |
1 u + 5 |
25% =
25100 =
1425% x 100
=
25100 x 100
= 25
80% x 25
=
80100 x 25
= 20
80% x 5 u
=
80100 x 5 u
= 4 u
Tommy had 190 less coins than Peter in the end. If another 190 coins are given to Tommy, both will have the same number of coins.
7 u + 95 = 1 u + 5 + 190
7 u - 1 u = 5 + 190 - 95
6 u = 100
1 u = 100 ÷ 6 = 25
Number of Tommy's coins at first
= 4 u
= 4 x 25
= 100
Answer: 100
