Fred and Tommy had 135 notebooks together. Tommy had 3 less notebooks than Fred. Both of them sold some of their notebooks. Tommy sold 20% more notebooks than what Fred sold. In the end, Tommy had half as many notebooks left as Fred. How many notebooks had Tommy left?
| |
Fred
(1) |
Tommy
(2) |
Make p the same
(2)x2 = (3) |
Comparing Fred
and Tommy at first |
3 more |
|
|
| Before |
69 |
66 |
132 |
| Change |
- 5 u |
- 6 u |
- 12 u |
| After |
2 p |
1 p |
2 p |
Number of notebooks that Tommy had at first
= (135 - 3) ÷ 2
= 132 ÷ 2
= 66
Number of notebooks that Fred had at first
= 66 + 3
= 69
Number of notebooks that Tommy sold in percent
= 100% + 20%
= 120%
120% =
120100 =
65 Make p the same.
(1) = (3)
69 - 5 u = 132 - 12 u
12 u - 5 u = 132 - 69
7 u = 63
1 u = 63 ÷ 7 = 9
Number of notebooks that Tommy had left
= 66 - 6 u
= 66 - 6 x 9
= 66 - 54
= 12
Answer(s): 12
