John and Luis had 51 markers together. John had 9 more markers than Luis. Both of them sold some of their markers. Luis sold 25% less markers than what John sold. In the end, Luis had half as many markers left as John. How many markers had John left?
| |
John
(1) |
Luis
(2) |
Make p the same
(2)x2 = (3) |
Comparing John
and Luis at first |
9 more |
|
|
| Before |
30 |
21 |
42 |
| Change |
- 4 u |
- 3 u |
- 6 u |
| After |
2 p |
1 p |
2 p |
Number of markers that Luis had at first
= (51 - 9) ÷ 2
= 42 ÷ 2
= 21
Number of markers that John had at first
= 21 + 9
= 30
Number of markers that Luis sold in percent
= 100% - 25%
= 75%
75% =
75100 =
34 Make p the same.
(1) = (3)
30 - 4 u = 42 - 6 u
6 u - 4 u = 42 - 30
2 u = 12
1 u = 12 ÷ 2 = 6
Number of markers that John had left
= 30 - 4 u
= 30 - 4 x 6
= 30 - 24
= 6
Answer(s): 6
