In an office building, a room contains 30 chairs. The number of chairs per row is 4 less than twice the number of rows. Find the number of rows.
A) 6 rows
B) 5 rows
C) 7 rows
D) 3 rows

Question

Quizplus · Accepted Answer

Let the number of rows be x. Then we have:
Number of chairs per row = 2x - 4
Total number of chairs = 30
So we have the equation:
x(2x-4) = 30
Simplifying, we get:
2x^2 - 4x - 30 = 0
Dividing through by 2, we get:
x^2 - 2x - 15 = 0
Factorizing, we get:
(x-5)(x+3) = 0
So, x = 5 or x = -3. We can't have a negative number of rows, so we take x = 5. Therefore, the number of rows is 5.

In an Office Building, a Room Contains 30 Chairs