We need to write the linear equation that is satisfied by (20,13) and (30,18). $18 - $13 $5 The slope is m = --------------- = -------- = $0.50/mile 30 - 20 10
We need to find the y-intercept of this function. To do that, start with the slope-intercept form y = mx + b
and subst. the y and x values from one of the two given points. Suppose we choose (20,$13):
$13 = ($0.50/mile)(20 miles) + b
Then $13 = $10 + b, and b = $3.
There's an up-front charge of $3 just to step into the taxi.
The equation in question is y = ($0.50/mile)x + $3.00 (answer)
