Valen and Zeph had 115 pencils together. Valen had 25 more pencils than Zeph. Both of them sold some of their pencils. Zeph sold 30% less pencils than what Valen sold. In the end, Zeph had half as many pencils left as Valen. How many pencils had Valen left?
| |
Valen
(1) |
Zeph
(2) |
Make p the same
(2)x2 = (3) |
Comparing Valen
and Zeph at first |
25 more |
|
|
| Before |
70 |
45 |
90 |
| Change |
- 10 u |
- 7 u |
- 14 u |
| After |
2 p |
1 p |
2 p |
Number of pencils that Zeph had at first
= (115 - 25) ÷ 2
= 90 ÷ 2
= 45
Number of pencils that Valen had at first
= 45 + 25
= 70
Number of pencils that Zeph sold in percent
= 100% - 30%
= 70%
70% =
70100 =
710 Make p the same.
(1) = (3)
70 - 10 u = 90 - 14 u
14 u - 10 u = 90 - 70
4 u = 20
1 u = 20 ÷ 4 = 5
Number of pencils that Valen had left
= 70 - 10 u
= 70 - 10 x 5
= 70 - 50
= 20
Answer(s): 20
