In a book shop, the number of post-it pads was
78 of the total number of post-it pads and notebooks together. Luke sold the post-it pads and notebooks in sets of 3 post-it pads and 10 notebooks. After selling all the notebooks, he still had 804 post-it pads left. How many post-it pads were in the book shop at first?
| |
Post-it Pads |
Notebooks |
| Before |
7x10 =
70 u |
1x10 =
10 u |
| Change |
- 3x1 =
- 3 u |
- 10x1 =
- 10 u |
| After |
804 |
0 |
Since all the notebooks were sold, the number of notebooks at first and the number of notebooks sold were the same. Make the number of notebooks at first and sold the same. LCM of 1 and 10 is 10.
Number of post-it pads sold
= 70 u - 3 u
= 67 u
67 u = 804
1 u = 804 ÷ 67 = 12
Number of post-it pads at first
= 70 u
= 70 x 12
= 840
Answer(s): 840
