Daniel and Andy had 59 pencils together. Daniel had 9 more pencils than Andy. Both of them sold some of their pencils. Andy sold 10% less pencils than what Daniel sold. In the end, Andy had half as many pencils left as Daniel. How many pencils had Daniel left?
| |
Daniel
(1) |
Andy
(2) |
Make p the same
(2)x2 = (3) |
Comparing Daniel
and Andy at first |
9 more |
|
|
| Before |
34 |
25 |
50 |
| Change |
- 10 u |
- 9 u |
- 18 u |
| After |
2 p |
1 p |
2 p |
Number of pencils that Andy had at first
= (59 - 9) ÷ 2
= 50 ÷ 2
= 25
Number of pencils that Daniel had at first
= 25 + 9
= 34
Number of pencils that Andy sold in percent
= 100% - 10%
= 90%
90% =
90100 =
910 Make p the same.
(1) = (3)
34 - 10 u = 50 - 18 u
18 u - 10 u = 50 - 34
8 u = 16
1 u = 16 ÷ 8 = 2
Number of pencils that Daniel had left
= 34 - 10 u
= 34 - 10 x 2
= 34 - 20
= 14
Answer(s): 14
