In a stationery shop, the number of rulers was
45 of the total number of rulers and post-it pads together. Perry sold the rulers and post-it pads in sets of 2 rulers and 3 post-it pads. After selling all the post-it pads, he still had 20 rulers left. How many rulers were in the stationery shop at first?
| |
Rulers |
Post-it Pads |
| Before |
4x3 =
12 u |
1x3 =
3 u |
| Change |
- 2x1 =
- 2 u |
- 3x1 =
- 3 u |
| After |
20 |
0 |
Since all the post-it pads were sold, the number of post-it pads at first and the number of post-it pads sold were the same. Make the number of post-it pads at first and sold the same. LCM of 1 and 3 is 3.
Number of rulers sold
= 12 u - 2 u
= 10 u
10 u = 20
1 u = 20 ÷ 10 = 2
Number of rulers at first
= 12 u
= 12 x 2
= 24
Answer(s): 24
