Some identical colouring books can be arranged in exactly 14 per row. If the same number of colouring books is arranged in rows of 9 colouring books each, there will be 4 more rows but short of 6 colouring books. How many colouring books are there altogether?
| |
14 per row |
9 per row |
| Number |
1 u |
1 u + 4 |
| Value |
14 u |
9 |
| Total value |
14 u |
9 u + 36 - 6 |
Number of rows if the colouring books are arranged in rows of 14 = 1 u
Number of rows if the colouring books are arranged in rows of 9 = 1 u + 4
Total number of colouring books if they are arranged in rows of 14
= 14 x 1 u
= 14 u
Total number of colouring books if they are arranged in rows of 9
= 9 x (1 u + 4) - 6
= 9 u + 36 - 6
= 9 u + 30
The total number of colouring books remains the same for both cases.
14 u = 9 u + 30
14 u - 9 u = 30
5 u = 30
1 u = 30 ÷ 5 = 6
Total number of colouring books
= 14 u
= 14 x 6
= 84
Answer(s): 84
