Answer:
r = P -t -s
Step-by-step explanation:
This is a one-step linear equation in r. Subtract the terms that don't contain r:
P = r + t + s . . . . . . . . . . given
The terms on the right that don't include r are (t+s). We want to subtract that to get r by itself.
P -(t+s) = r +(t+s) -(t+s) . . . subtract (t+s)
P -t -s = r . . . . . . . . . . . . . . simplify
r = P - t - s
I guess you want to find the average speed for the whole journey
average speed = distance travelled / time
the distance from home to the shop = speed * time = 0.5*10 = 5 miles
time for travelling back = distance / speed = 5/30 = 1/6 hours
average speed for whole journey = 10 / (1/2 + 1/6) = 10 * 3 / 2 = 15 mph
Answer:
37 minutes = 55 1/2 miles. 1 hour=90 miles