This equation shows how the cost of a plumber's visit is related to its duration in hours. c = 24.9d + 11.4 The variable d repre
sents the duration of the visit in hours, and the variable c represents the cost. What is the duration, in hours, of a plumber's visit that costs $31.32?
The correct answer would be 8/10 of an hour or 48 minutes.
To solve this, you would plug in the 31.32 into the cost. You would then subtract 11.4 from both sides to isolate the d term. You would then be left with 19.92=24.9d. You would then divide both sides by 24.9, to solve for the d term, and you would get d=.8
