It is given in the question that, one fire extinguisher be available for every 6000 square feet in the building .
And number of fire extinguishers needed for building that has 135,000 square feet are x .
So the required equation is
[tex] 6000x = 135000 [/tex]
Dividing both sides by 6000
[tex] x = \frac{135000}{6000} = 22.50 [/tex]
And on rounding, we will get 23.
And that's the required answer.
