PSLEIn a school hall, chairs were arranged in rows such that there were exactly 22 chairs in each row. For a concert, Cody brought 4 more chairs into the school hall and rearranged all the chairs. There are now exactly 9 chairs in each row and 12 more rows than before. How many chairs are there in the school hall for the concert in the end?
|
Before |
After |
Number |
1 u |
1 u + 12 |
Value |
22 |
9 |
Total value |
22 u + 4 |
9 u + 108 |
Number of rows at first = 1 u
Number of rows in the end = 1 u + 12
Number of chairs at first after the 4 chairs were brought in
= 22 x 1 u + 4
= 22 u + 4
Number of chairs in the end
= 9 x (1 u + 12)
= 9 u + 108
The total number of chairs is equal.
22 u + 4 = 9 u + 108
22 u - 9 u = 108 - 4
13 u = 104
1 u = 104 ÷ 13 = 8
Number of chairs in the end
= 9 u + 108
= 9 x 8 + 108
= 180
Answer(s): 180