Question

Independent Practice

Answer 1

Answer:

D.

d = 3t; 90 mi

Step-by-step explanation:

Bicycling A bicyclist traveled at a constant speed during a timed practice period. Write a proportion to find the distance the cyclist traveled in 30 min.

elapsed time    distance

10 min               3 mi

25 min               7.5 mi

Graph it. :)

Start at (0,0), then at 10 min. on the x-axis, go 3 spaces up on the y-axis and plot a point. Do the same for 25 min. and 7.5 miles. Draw a line through all of those points, and see where the line hits on the y-axis when the x-axis is at 30 min. :)

If two things vary directly it means their ratio is a constant.  Therefore from the formula rt=d. r=d/t,  r=3/10 or 7.5/25  which reduces to 3/10.  This is the constant speed,the lable is mi/min.  Now use  (d/30)=(3/10)  and solve for d.  Cross multiply and 10d=90, or d=9 mi