Pierre had 90 more pens than Henry. Pierre gave 20% of his pens to Henry. Henry in return gave 50% of his pens to Pierre. In the end, Pierre had 252 more pens than Henry. How many pens did Pierre have at first?
| |
Pierre |
Henry |
Comparing Pierre
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
Pierre had 252 more pens than Henry in the end. If another 252 pens are given to Henry, both will have the same number of pens.
7 u + 81 = 3 u + 9 + 252
7 u - 3 u = 9 + 252 - 81
6 u = 180
1 u = 180 ÷ 6 = 30
Number of Pierre's pens at first
= 5 u + 90
= 5 x 30 + 90
= 150 + 90
= 240
Answer: 240
