How long does it take to drive 760 miles at 65 miles per hour?

Answer 1

Use the fundamental equation:

Average Speed (s) = distance (d) / time (t)

The way you can remember it, a speed is going to be in "mph" (or something like that). That's miles / hour. Miles is a distance and hours is a time (or: distance over time.)

Solve for t:

s = d / t

st = d

t = d/s (time is equal to distance divided by speed)

In the question, you have a distance and a speed:

d = 760 miles

s = 65 miles / hour

Plug d and s into the equation and you can find a numerical value for t.

t = d/s

t = (760 miles) / (65 miles / hour ) <-- miles cancels out, leaving hours

t = (760 / 65) hours

t ~= 11.6923 hours (carry a few decimals, so you can convert them into minutes)

11.6923 hours = 11 hours + 0.6923 hours

We'll leave the 11 hours as is, because it's a whole number and convert what's left to minutes.

Conversion factor: 1 hour = 60 minutes <--- write this as a fraction (next step)

(0.6923 hours) x (60 minutes / 1 hour) = (0.6923 x 60) minutes

(0.6923 x 60) minutes ~= 41.54 ~= 42 minutes

Therefore it will take about 11 hours and 42 minutes to travel 760 miles at 65 mph.

If you care about significant figures, both 760 miles and 65 mph both have 2 significant figures, therefore you'd round your answer (11.69 hours) to 12 hours and not worry about minutes.