The Occupational Safety and health Administration (OSHA) estblished permissible sound exposures in the work-place. This is modeled by the equation: S=-2.817H + 108.9

Use the formula for the problem:

S=maximun permissible sound level in decibels

H=number of hours of exposure

How long can you be exposed to receive a maximum sound level of 105 decibels?

6 answers

Are you sure that's a negative 2.817 in your equation?
Are you sure that's a negative 2.817 in your equation?

Yes it is a negative. It worked for the other problems.
OK. Then please follow PsyDag's advice and substitute and solve for H.
Yes I have tried calculating the problem. The book says the answer is 1.38. I am not getting this answer.
105 = -2.817H + 108.9
105 - 108.9 = -2.817H
-3.9 / -2.817 = H
1.38 = H
Your question:

The Occupational Safety and health Administration (OSHA) estblished permissible sound exposures in the work-place. This is modeled by the equation: S = -2.817H + 108.9

Use the formula for the problem:

S = maximun permissible sound level in decibels

H = number of hours of exposure

How long can you be exposed to receive a maximum sound level of 105 decibels?

We replace S with 105.

105 = =-2.817H + 108.9

We now solve for H.

105 - 108.9 = -2.817H

-3.9 = -2.817H

We now divide both sides by -2.817 to find H.

-3.9/-2.817 = H

1.38 hours = H

Done!