In the seminar room, chairs were arranged in rows of 11. During a workshop, 25 chairs were added to accommodate the number of people. The chairs were rearranged to form rows of 9. 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 seminar room in the end?
|
First arrangement |
Second arrangement |
Number |
1 u |
1 u + 5 |
Value |
11 |
9 |
Total value |
11 u |
9 u + 45 |
(a)
Number of chairs in the extra 5 rows
= 5 x 9
= 45
(b)
Total number of chairs in the first arrangement
= 1 u x 11
= 11 u
Total number of chairs in the second arrangement
= 9(1 u + 5)
= 9 u + 45
If 25 chairs were included in the first arrangement, the total number of chairs in the first arrangement and the second arrangement will be the same.
11 u + 25 = 9 u + 45
11 u - 9 u = 45 - 25
2 u = 20
1 u = 20 ÷ 2 = 10
Number of chairs in the seminar room in the end
= 10 x 11 + 25
= 110 + 25
= 135
Answer(s): (a) 45; (b) 135