Andy had 200 more coins than Charlie. Andy gave 20% of his coins to Charlie. Charlie in return gave 50% of his coins to Andy. In the end, Andy had 806 more coins than Charlie. How many coins did Andy have at first?
| |
Andy |
Charlie |
Comparing Andy
and Peter at first |
200 more |
|
| Before |
5 u + 200 |
5 u |
| Change 1 |
- 1 u - 40 |
+ 1 u + 40 |
| After 1 |
4 u + 160 |
6 u + 40 |
| Change 2 |
+ 3 u + 20 |
- 3 u - 20 |
| After 2 |
7 u + 180 |
3 u + 20 |
20% =
20100 =
1520% x 200
=
20100 x 200
= 40
50% x 40
=
50100 x 40
= 20
50% x 6 u
=
50100 x 6 u
= 3 u
Andy had 806 more coins than Charlie in the end. If another 806 coins are given to Charlie, both will have the same number of coins.
7 u + 180 = 3 u + 20 + 806
7 u - 3 u = 20 + 806 - 180
17 u = 646
1 u = 646 ÷ 17 = 38
Number of Andy's coins at first
= 5 u + 200
= 5 x 38 + 200
= 190 + 200
= 390
Answer: 390
