In the seminar room, chairs were arranged in rows of 13. During a workshop, 27 chairs were added to accommodate the number of people. The chairs were rearranged to form rows of 9. As a result, there were 7 more rows.
- How many chairs were there in the extra 7 rows?
- How many chairs were there in the seminar room in the end?
|
First arrangement |
Second arrangement |
Number |
1 u |
1 u + 7 |
Value |
13 |
9 |
Total value |
13 u |
9 u + 63 |
(a)
Number of chairs in the extra 7 rows
= 7 x 9
= 63
(b)
Total number of chairs in the first arrangement
= 1 u x 13
= 13 u
Total number of chairs in the second arrangement
= 9(1 u + 7)
= 9 u + 63
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.
13 u + 27 = 9 u + 63
13 u - 9 u = 63 - 27
4 u = 36
1 u = 36 ÷ 4 = 9
Number of chairs in the seminar room in the end
= 9 x 13 + 27
= 117 + 27
= 144
Answer(s): (a) 63; (b) 144