There were some rows of chairs in a school field. Each row had 7 chairs. When Sabrina brought in 3 extra chairs and rearranged all the chairs, there were 4 chairs in each row and 3 more rows than before. How many chairs were there at first?
|
First arrangement |
Second arrangement |
Number |
1 u |
1 u + 3 |
Value |
7 |
4 |
Total value |
7 u |
4 u + 12 |
If another 3 chairs are added in the first arrangement, the total number of chairs in the first arrangement and the second arrangement will be the same.
7 u + 3 = 4 u + 12
7 u - 4 u = 12 - 3
3 u = 9
1 u = 9 ÷ 3 = 3
Number of chairs at first
= 7 u
= 7 x 3
= 21
Answer(s): 21