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
