Eric had 90 more cards than Carl. Eric gave 20% of his cards to Carl. Carl in return gave 50% of his cards to Eric. In the end, Eric had 228 more cards than Carl. How many cards did Eric have at first?
| |
Eric |
Carl |
Comparing Eric
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
Eric had 228 more cards than Carl in the end. If another 228 cards are given to Carl, both will have the same number of cards.
7 u + 81 = 3 u + 9 + 228
7 u - 3 u = 9 + 228 - 81
6 u = 156
1 u = 156 ÷ 6 = 26
Number of Eric's cards at first
= 5 u + 90
= 5 x 26 + 90
= 130 + 90
= 220
Answer: 220
