In the school hall, chairs were arranged in rows of 18. During a function, 35 chairs were added to accommodate the number of people. The chairs were rearranged to form rows of 13. As a result, there were 5 more rows.
- How many chairs were there in the extra 5 rows?
- How many chairs were there in the school hall in the end?
|
First arrangement |
Second arrangement |
Number |
1 u |
1 u + 5 |
Value |
18 |
13 |
Total value |
18 u |
13 u + 65 |
(a)
Number of chairs in the extra 5 rows
= 5 x 13
= 65
(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 + 5)
= 13 u + 65
If 35 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 + 35 = 13 u + 65
18 u - 13 u = 65 - 35
5 u = 30
1 u = 30 ÷ 5 = 6
Number of chairs in the school hall in the end
= 6 x 18 + 35
= 108 + 35
= 143
Answer(s): (a) 65; (b) 143