Henry and Ben had 69 pens together. Ben had 7 less pens than Henry. Both of them sold some of their pens. Ben sold 10% more pens than what Henry sold. In the end, Ben had half as many pens left as Henry. How many pens had Ben left?
| |
Henry
(1) |
Ben
(2) |
Make p the same
(2)x2 = (3) |
Comparing Henry
and Ben at first |
7 more |
|
|
| Before |
38 |
31 |
62 |
| Change |
- 10 u |
- 11 u |
- 22 u |
| After |
2 p |
1 p |
2 p |
Number of pens that Ben had at first
= (69 - 7) ÷ 2
= 62 ÷ 2
= 31
Number of pens that Henry had at first
= 31 + 7
= 38
Number of pens that Ben sold in percent
= 100% + 10%
= 110%
110% =
110100 =
1110 Make p the same.
(1) = (3)
38 - 10 u = 62 - 22 u
22 u - 10 u = 62 - 38
12 u = 24
1 u = 24 ÷ 12 = 2
Number of pens that Ben had left
= 31 - 11 u
= 31 - 11 x 2
= 31 - 22
= 9
Answer(s): 9
