Henry had 100 more marbles than Oliver. Henry gave 20% of his marbles to Oliver. Oliver in return gave 50% of his marbles to Henry. In the end, Henry had 241 more marbles than Oliver. How many marbles did Henry have at first?
| |
Henry |
Oliver |
Comparing Henry
and Peter at first |
100 more |
|
| Before |
5 u + 100 |
5 u |
| Change 1 |
- 1 u - 20 |
+ 1 u + 20 |
| After 1 |
4 u + 80 |
6 u + 20 |
| Change 2 |
+ 3 u + 10 |
- 3 u - 10 |
| After 2 |
7 u + 90 |
3 u + 10 |
20% =
20100 =
1520% x 100
=
20100 x 100
= 20
50% x 20
=
50100 x 20
= 10
50% x 6 u
=
50100 x 6 u
= 3 u
Henry had 241 more marbles than Oliver in the end. If another 241 marbles are given to Oliver, both will have the same number of marbles.
7 u + 90 = 3 u + 10 + 241
7 u - 3 u = 10 + 241 - 90
7 u = 161
1 u = 161 ÷ 7 = 23
Number of Henry's marbles at first
= 5 u + 100
= 5 x 23 + 100
= 115 + 100
= 215
Answer: 215
