Tim and John had 159 pencils together. John had 5 less pencils than Tim. Both of them sold some of their pencils. John sold 10% more pencils than what Tim sold. In the end, John had half as many pencils left as Tim. How many pencils had John left?
| |
Tim
(1) |
John
(2) |
Make p the same
(2)x2 = (3) |
Comparing Tim
and John at first |
5 more |
|
|
| Before |
82 |
77 |
154 |
| Change |
- 10 u |
- 11 u |
- 22 u |
| After |
2 p |
1 p |
2 p |
Number of pencils that John had at first
= (159 - 5) ÷ 2
= 154 ÷ 2
= 77
Number of pencils that Tim had at first
= 77 + 5
= 82
Number of pencils that John sold in percent
= 100% + 10%
= 110%
110% =
110100 =
1110 Make p the same.
(1) = (3)
82 - 10 u = 154 - 22 u
22 u - 10 u = 154 - 82
12 u = 72
1 u = 72 ÷ 12 = 6
Number of pencils that John had left
= 77 - 11 u
= 77 - 11 x 6
= 77 - 66
= 11
Answer(s): 11
