Some identical workbooks can be arranged in exactly 12 per row. If the same number of workbooks is arranged in rows of 8 workbooks each, there will be 4 more rows but short of 4 workbooks. How many workbooks are there altogether?
| |
12 per row |
8 per row |
| Number |
1 u |
1 u + 4 |
| Value |
12 u |
8 |
| Total value |
12 u |
8 u + 32 - 4 |
Number of rows if the workbooks are arranged in rows of 12 = 1 u
Number of rows if the workbooks are arranged in rows of 8 = 1 u + 4
Total number of workbooks if they are arranged in rows of 12
= 12 x 1 u
= 12 u
Total number of workbooks if they are arranged in rows of 8
= 8 x (1 u + 4) - 4
= 8 u + 32 - 4
= 8 u + 28
The total number of workbooks remains the same for both cases.
12 u = 8 u + 28
12 u - 8 u = 28
4 u = 28
1 u = 28 ÷ 4 = 7
Total number of workbooks
= 12 u
= 12 x 7
= 84
Answer(s): 84
