In the seminar room, chairs were arranged in rows of 15. During a workshop, 39 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 seminar room in the end?
|
First arrangement |
Second arrangement |
Number |
1 u |
1 u + 5 |
Value |
15 |
13 |
Total value |
15 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 15
= 15 u
Total number of chairs in the second arrangement
= 13(1 u + 5)
= 13 u + 65
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.
15 u + 39 = 13 u + 65
15 u - 13 u = 65 - 39
2 u = 26
1 u = 26 ÷ 2 = 13
Number of chairs in the seminar room in the end
= 13 x 15 + 39
= 195 + 39
= 234
Answer(s): (a) 65; (b) 234