Oscar had 50 more marbles than Carl. Oscar gave 20% of his marbles to Carl. Carl in return gave 50% of his marbles to Oscar. In the end, Carl had 100 less marbles than Oscar. How many marbles did Oscar have at first?
| |
Oscar |
Carl |
Comparing Oscar
and Peter at first |
50 more |
|
| Before |
5 u + 50 |
5 u |
| Change 1 |
- 1 u - 10 |
+ 1 u + 10 |
| After 1 |
4 u + 40 |
6 u + 10 |
| Change 2 |
+ 3 u + 5 |
- 3 u - 5 |
| After 2 |
7 u + 45 |
3 u + 5 |
20% =
20100 =
1520% x 50
=
20100 x 50
= 10
50% x 10
=
50100 x 10
= 5
50% x 6 u
=
50100 x 6 u
= 3 u
Carl had 100 less marbles than Oscar in the end. If another 100 marbles are given to Carl, both will have the same number of marbles.
7 u + 45 = 3 u + 5 + 100
7 u - 3 u = 5 + 100 - 45
4 u = 60
1 u = 60 ÷ 4 = 30
Number of Carl's marbles at first
= 5 u
= 5 x 30
= 150
Answer: 150
