Charlie and Cole had 46 pens together. Charlie had 10 more pens than Cole. Both of them sold some of their pens. Cole sold 30% less pens than what Charlie sold. In the end, Cole had half as many pens left as Charlie. How many pens had Charlie left?
| |
Charlie
(1) |
Cole
(2) |
Make p the same
(2)x2 = (3) |
Comparing Charlie
and Cole at first |
10 more |
|
|
| Before |
28 |
18 |
36 |
| Change |
- 10 u |
- 7 u |
- 14 u |
| After |
2 p |
1 p |
2 p |
Number of pens that Cole had at first
= (46 - 10) ÷ 2
= 36 ÷ 2
= 18
Number of pens that Charlie had at first
= 18 + 10
= 28
Number of pens that Cole sold in percent
= 100% - 30%
= 70%
70% =
70100 =
710 Make p the same.
(1) = (3)
28 - 10 u = 36 - 14 u
14 u - 10 u = 36 - 28
4 u = 8
1 u = 8 ÷ 4 = 2
Number of pens that Charlie had left
= 28 - 10 u
= 28 - 10 x 2
= 28 - 20
= 8
Answer(s): 8
