There were some rows of chairs in a canteen. Each row had 7 chairs. When Diana brought in 17 extra chairs and rearranged all the chairs, there were 5 chairs in each row and 5 more rows than before. How many chairs were there at first?
|
First arrangement |
Second arrangement |
Number |
1 u |
1 u + 5 |
Value |
7 |
5 |
Total value |
7 u |
5 u + 25 |
If another 17 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 + 17 = 5 u + 25
7 u - 5 u = 25 - 17
2 u = 8
1 u = 8 ÷ 2 = 4
Number of chairs at first
= 7 u
= 7 x 4
= 28
Answer(s): 28