Jack rode his bike 10 miles in 30 min. What was his approx. speed in mph?

Step-by-step explanation:

mph = miles per hour number of  miles traveled in one hour.

You know how far Jack traveled (10 miles)  in 30min (1/2 hour).  

If he continued at the same rate for another 1/2 hour (for a total of 1 hour), how far would he have traveled?  He would have traveled 20 miles in one hour; 20mph

You can use this formula to calculate his speed:

Rate = Distance * Time  , where Rate is mph, Distance is miles, Time is hours

    R = D / T

    R = 10 / 0.5         30 min is 30/60 hours or 1/2 or 0.5

    R =  20mph

i pretty sure it is