Mark had 70 more pens than Albert. Mark gave 20% of his pens to Albert. Albert in return gave 50% of his pens to Mark. In the end, Mark had 204 more pens than Albert. How many pens did Mark have at first?
| |
Mark |
Albert |
Comparing Mark
and Peter at first |
70 more |
|
| Before |
5 u + 70 |
5 u |
| Change 1 |
- 1 u - 14 |
+ 1 u + 14 |
| After 1 |
4 u + 56 |
6 u + 14 |
| Change 2 |
+ 3 u + 7 |
- 3 u - 7 |
| After 2 |
7 u + 63 |
3 u + 7 |
20% =
20100 =
1520% x 70
=
20100 x 70
= 14
50% x 14
=
50100 x 14
= 7
50% x 6 u
=
50100 x 6 u
= 3 u
Mark had 204 more pens than Albert in the end. If another 204 pens are given to Albert, both will have the same number of pens.
7 u + 63 = 3 u + 7 + 204
7 u - 3 u = 7 + 204 - 63
4 u = 148
1 u = 148 ÷ 4 = 37
Number of Mark's pens at first
= 5 u + 70
= 5 x 37 + 70
= 185 + 70
= 255
Answer: 255
