Carl had 180 more pens than Billy. Carl gave 20% of his pens to Billy. Billy in return gave 50% of his pens to Carl. In the end, Billy had 699 less pens than Carl. How many pens did Carl have at first?
| |
Carl |
Billy |
Comparing Carl
and Peter at first |
180 more |
|
| Before |
5 u + 180 |
5 u |
| Change 1 |
- 1 u - 36 |
+ 1 u + 36 |
| After 1 |
4 u + 144 |
6 u + 36 |
| Change 2 |
+ 3 u + 18 |
- 3 u - 18 |
| After 2 |
7 u + 162 |
3 u + 18 |
20% =
20100 =
1520% x 180
=
20100 x 180
= 36
50% x 36
=
50100 x 36
= 18
50% x 6 u
=
50100 x 6 u
= 3 u
Billy had 699 less pens than Carl in the end. If another 699 pens are given to Billy, both will have the same number of pens.
7 u + 162 = 3 u + 18 + 699
7 u - 3 u = 18 + 699 - 162
4 u = 555
1 u = 555 ÷ 4 = 37
Number of Billy's pens at first
= 5 u
= 5 x 37
= 185
Answer: 185
