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 $d$ $d$ :

$21 = 1.50 d + 3$ $21 = 1.50d + 3$

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

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

$18 = 1.50 d + 0$ $18 = 1.50d + 0$

$18 = 1.50 d$ $18 = 1.50d$

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

$\frac{18}{1.50} = \frac{1.50 d}{1.50}$ $18/color(red)(1.50) = (1.50d)/color(red)(1.50)$

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

$12 = d$

$d = 12$