Ivan and Ian had 80 pens together. Ian had 8 less pens than Ivan. Both of them sold some of their pens. Ian sold 20% more pens than what Ivan sold. In the end, Ian had half as many pens left as Ivan. How many pens had Ian left?
| |
Ivan
(1) |
Ian
(2) |
Make p the same
(2)x2 = (3) |
Comparing Ivan
and Ian at first |
8 more |
|
|
| Before |
44 |
36 |
72 |
| Change |
- 5 u |
- 6 u |
- 12 u |
| After |
2 p |
1 p |
2 p |
Number of pens that Ian had at first
= (80 - 8) ÷ 2
= 72 ÷ 2
= 36
Number of pens that Ivan had at first
= 36 + 8
= 44
Number of pens that Ian sold in percent
= 100% + 20%
= 120%
120% =
120100 =
65 Make p the same.
(1) = (3)
44 - 5 u = 72 - 12 u
12 u - 5 u = 72 - 44
7 u = 28
1 u = 28 ÷ 7 = 4
Number of pens that Ian had left
= 36 - 6 u
= 36 - 6 x 4
= 36 - 24
= 12
Answer(s): 12
