In the school hall, chairs were arranged in rows of 15. During a function, 10 chairs were added to accommodate the number of people. The chairs were rearranged to form rows of 10. 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 school hall in the end?
|
First arrangement |
Second arrangement |
Number |
1 u |
1 u + 5 |
Value |
15 |
10 |
Total value |
15 u |
10 u + 50 |
(a)
Number of chairs in the extra 5 rows
= 5 x 10
= 50
(b)
Total number of chairs in the first arrangement
= 1 u x 15
= 15 u
Total number of chairs in the second arrangement
= 10(1 u + 5)
= 10 u + 50
If 10 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 + 10 = 10 u + 50
15 u - 10 u = 50 - 10
5 u = 40
1 u = 40 ÷ 5 = 8
Number of chairs in the school hall in the end
= 8 x 15 + 10
= 120 + 10
= 130
Answer(s): (a) 50; (b) 130