Bobby had 60 more cards than Sam. Bobby gave 20% of his cards to Sam. Sam in return gave 50% of his cards to Bobby. In the end, Sam had 135 less cards than Bobby. How many cards did Bobby have at first?
| |
Bobby |
Sam |
Comparing Bobby
and Peter at first |
60 more |
|
| Before |
5 u + 60 |
5 u |
| Change 1 |
- 1 u - 12 |
+ 1 u + 12 |
| After 1 |
4 u + 48 |
6 u + 12 |
| Change 2 |
+ 3 u + 6 |
- 3 u - 6 |
| After 2 |
7 u + 54 |
3 u + 6 |
20% =
20100 =
1520% x 60
=
20100 x 60
= 12
50% x 12
=
50100 x 12
= 6
50% x 6 u
=
50100 x 6 u
= 3 u
Sam had 135 less cards than Bobby in the end. If another 135 cards are given to Sam, both will have the same number of cards.
7 u + 54 = 3 u + 6 + 135
7 u - 3 u = 6 + 135 - 54
4 u = 87
1 u = 87 ÷ 4 = 29
Number of Sam's cards at first
= 5 u
= 5 x 29
= 145
Answer: 145
