David had 160 more stickers than Billy. David gave 25% of his stickers to Billy. Billy in return gave 60% of his stickers to David. In the end, Billy had 478 less stickers than David. How many stickers did David have at first?
| |
David |
Billy |
Comparing David
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 |
+ 3 u + 24 |
- 3 u - 24 |
| After 2 |
6 u + 144 |
2 u + 16 |
25% =
25100 =
1425% x 160
=
25100 x 160
= 40
60% x 40
=
60100 x 40
= 24
60% x 5 u
=
60100 x 5 u
= 3 u
Billy had 478 less stickers than David in the end. If another 478 stickers are given to Billy, both will have the same number of stickers.
6 u + 144 = 2 u + 16 + 478
6 u - 2 u = 16 + 478 - 144
4 u = 350
1 u = 350 ÷ 4 = 25
Number of Billy's stickers at first
= 4 u
= 4 x 25
= 100
Answer: 100
