PSLEIn a school hall, chairs were arranged in rows such that there were exactly 23 chairs in each row. For a concert, Paul removed 5 chairs from the school hall and rearranged all the chairs. There are now exactly 7 chairs in each row and 13 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 + 13 |
Value |
23 |
7 |
Total value |
23 u - 5 |
7 u + 91 |
Number of rows at first = 1 u
Number of rows in the end = 1 u + 13
Number of chairs at first after the 5 chairs were removed
= 23 x 1 u - 5
= 23 u - 5
Number of chairs in the end
= 7 x (1 u + 13)
= 7 u + 91
The total number of chairs is equal.
23 u - 5 = 7 u + 91
23 u - 7 u = 91 + 5
16 u = 96
1 u = 96 ÷ 16 = 6
Number of chairs in the end
= 7 u + 91
= 7 x 6 + 91
= 133
Answer(s): 133