In the seminar room, chairs were arranged in rows of 12. During a workshop, 39 chairs were added to accommodate the number of people. The chairs were rearranged to form rows of 9. As a result, there were 8 more rows.
- How many chairs were there in the extra 8 rows?
- How many chairs were there in the seminar room in the end?
|
First arrangement |
Second arrangement |
Number |
1 u |
1 u + 8 |
Value |
12 |
9 |
Total value |
12 u |
9 u + 72 |
(a)
Number of chairs in the extra 8 rows
= 8 x 9
= 72
(b)
Total number of chairs in the first arrangement
= 1 u x 12
= 12 u
Total number of chairs in the second arrangement
= 9(1 u + 8)
= 9 u + 72
If 39 chairs were included in the first arrangement, the total number of chairs in the first arrangement and the second arrangement will be the same.
12 u + 39 = 9 u + 72
12 u - 9 u = 72 - 39
3 u = 33
1 u = 33 ÷ 3 = 11
Number of chairs in the seminar room in the end
= 11 x 12 + 39
= 132 + 39
= 171
Answer(s): (a) 72; (b) 171