Tom and Cole had 45 notebooks together. Tom had 7 more notebooks than Cole. Both of them sold some of their notebooks. Cole sold 20% less notebooks than what Tom sold. In the end, Cole had half as many notebooks left as Tom. How many notebooks had Tom left?
| |
Tom
(1) |
Cole
(2) |
Make p the same
(2)x2 = (3) |
Comparing Tom
and Cole at first |
7 more |
|
|
| Before |
26 |
19 |
38 |
| Change |
- 5 u |
- 4 u |
- 8 u |
| After |
2 p |
1 p |
2 p |
Number of notebooks that Cole had at first
= (45 - 7) ÷ 2
= 38 ÷ 2
= 19
Number of notebooks that Tom had at first
= 19 + 7
= 26
Number of notebooks that Cole sold in percent
= 100% - 20%
= 80%
80% =
80100 =
45 Make p the same.
(1) = (3)
26 - 5 u = 38 - 8 u
8 u - 5 u = 38 - 26
3 u = 12
1 u = 12 ÷ 3 = 4
Number of notebooks that Tom had left
= 26 - 5 u
= 26 - 5 x 4
= 26 - 20
= 6
Answer(s): 6
