Warren and John had 117 notebooks together. John had 7 less notebooks than Warren. Both of them sold some of their notebooks. John sold 10% more notebooks than what Warren sold. In the end, John had half as many notebooks left as Warren. How many notebooks had John left?
| |
Warren
(1) |
John
(2) |
Make p the same
(2)x2 = (3) |
Comparing Warren
and John at first |
7 more |
|
|
| Before |
62 |
55 |
110 |
| Change |
- 10 u |
- 11 u |
- 22 u |
| After |
2 p |
1 p |
2 p |
Number of notebooks that John had at first
= (117 - 7) ÷ 2
= 110 ÷ 2
= 55
Number of notebooks that Warren had at first
= 55 + 7
= 62
Number of notebooks that John sold in percent
= 100% + 10%
= 110%
110% =
110100 =
1110 Make p the same.
(1) = (3)
62 - 10 u = 110 - 22 u
22 u - 10 u = 110 - 62
12 u = 48
1 u = 48 ÷ 12 = 4
Number of notebooks that John had left
= 55 - 11 u
= 55 - 11 x 4
= 55 - 44
= 11
Answer(s): 11
