Some identical workbooks can be arranged in exactly 15 per row. If the same number of workbooks is arranged in rows of 10 workbooks each, there will be 4 more rows but short of 5 workbooks. How many workbooks are there altogether?
|
15 per row |
10 per row |
Number |
1 u |
1 u + 4 |
Value |
15 u |
10 |
Total value |
15 u |
10 u + 40 - 5 |
Number of rows if the workbooks are arranged in rows of 15 = 1 u
Number of rows if the workbooks are arranged in rows of 10 = 1 u + 4
Total number of workbooks if they are arranged in rows of 15
= 15 x 1 u
= 15 u
Total number of workbooks if they are arranged in rows of 10
= 10 x (1 u + 4) - 5
= 10 u + 40 - 5
= 10 u + 35
The total number of workbooks remains the same for both cases.
15 u = 10 u + 35
15 u - 10 u = 35
5 u = 35
1 u = 35 ÷ 5 = 7
Total number of workbooks
= 15 u
= 15 x 7
= 105
Answer(s): 105