In the school hall, chairs were arranged in rows of 13. During a function, 21 chairs were added to accommodate the number of people. The chairs were rearranged to form rows of 10. As a result, there were 6 more rows.
- How many chairs were there in the extra 6 rows?
- How many chairs were there in the school hall in the end?
|
First arrangement |
Second arrangement |
Number |
1 u |
1 u + 6 |
Value |
13 |
10 |
Total value |
13 u |
10 u + 60 |
(a)
Number of chairs in the extra 6 rows
= 6 x 10
= 60
(b)
Total number of chairs in the first arrangement
= 1 u x 13
= 13 u
Total number of chairs in the second arrangement
= 10(1 u + 6)
= 10 u + 60
If 21 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 + 21 = 10 u + 60
13 u - 10 u = 60 - 21
3 u = 39
1 u = 39 ÷ 3 = 13
Number of chairs in the school hall in the end
= 13 x 13 + 21
= 169 + 21
= 190
Answer(s): (a) 60; (b) 190