In a bookstore, the number of markers was
23 of the total number of markers and rulers together. Cody sold the markers and rulers in sets of 1 marker and 3 rulers. After selling all the rulers, he still had 15 markers left. How many rulers were in the bookstore at first?
|
Markers |
Rulers |
Before |
2x3 = 6 u |
1x3 = 3 u |
Change |
- 1x1 = - 1 u |
- 3x1 = - 3 u |
After |
15 |
0 |
Since all the rulers were sold, the number of rulers at first and the number of rulers sold were the same. Make the number of rulers at first and sold the same. LCM of 1 and 3 is 3.
Number of markers sold
= 6 u - 1 u
= 5 u
5 u = 15
1 u = 15 ÷ 5 = 3
Number of rulers at first
= 3 u
= 3 x 3
= 9
Answer(s): 9