Some identical comics can be arranged in exactly 10 per row. If the same number of comics is arranged in rows of 7 comics each, there will be 4 more rows and 2 comics left over. How many comics are there altogether?
| |
10 per row |
7 per row |
| Number |
1 u |
1 u + 4 |
| Value |
10 |
7 |
| Total value |
10 u |
7 u + 28 + 2 |
Number of rows if the comics are arranged in rows of 10 = 1 u
Number of rows if the comics are arranged in rows of 7 = 1 u + 4
Total number of comics if they are arranged in rows of 10
= 10 x 1 u
= 10 u
Total number of comics if they are arranged in rows of 7
= 7 x (1 u + 4) + 2
= 7 u + 28 + 2
= 7 u + 30
The total number of comics remains the same for both cases.
10 u = 7 u + 30
10 u - 7 u = 30
3 u = 30
1 u = 30 ÷ 3 = 10
Total number of comics
= 10 u
= 10 x 10
= 100
Answer(s): 100
