A taxi company charges $3 to pick up a fare and $1.50 for each unit of distance driven. How many units did the rider go if the total fare was $21?

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Answer 1 · 2017-01-29T00:23:38

B. 12

We equate the fare to the formula for the fare and solve for #d#:

#21 = 1.50d + 3#

First, subtract #color(red)(3)# from each side of the equation to isolate the #d# term while keeping the equation balanced:

#21 - color(red)(3) = 1.50d + 3 - color(red)(3)#

#18 = 1.50d + 0#

#18 = 1.50d#

Now, divide each side of the equation by #color(red)(1.50)# to solve for #d# while keeping the equation balanced:

#18/color(red)(1.50) = (1.50d)/color(red)(1.50)#

#12 = (color(red)cancel(color(black)(1.50))d)/cancel(color(red)(1.50))#

#12 = d#

#d = 12#