In the school hall, chairs were arranged in rows of 18. During a function, 27 chairs were added to accommodate the number of people. The chairs were rearranged to form rows of 13. As a result, there were 4 more rows.
- How many chairs were there in the extra 4 rows?
- How many chairs were there in the school hall in the end?
|
First arrangement |
Second arrangement |
Number |
1 u |
1 u + 4 |
Value |
18 |
13 |
Total value |
18 u |
13 u + 52 |
(a)
Number of chairs in the extra 4 rows
= 4 x 13
= 52
(b)
Total number of chairs in the first arrangement
= 1 u x 18
= 18 u
Total number of chairs in the second arrangement
= 13(1 u + 4)
= 13 u + 52
If 27 chairs were included in the first arrangement, the total number of chairs in the first arrangement and the second arrangement will be the same.
18 u + 27 = 13 u + 52
18 u - 13 u = 52 - 27
5 u = 25
1 u = 25 ÷ 5 = 5
Number of chairs in the school hall in the end
= 5 x 18 + 27
= 90 + 27
= 117
Answer(s): (a) 52; (b) 117