Question

On their trip to Washington, DC, Jen and her parents drove 3 hours at a speed of 60 mph and then 3 hours at a speed of 40 mph. Driving back, they spent the same time. What was their driving speed on the way back?

Answer 1

Answer:

50 mi/h

Step-by-step explanation:

d - distance, v - speed, t - time

d = vt ⇒ v = $\frac{d}{t}$

d = 3 × 60 + 3 × 40 = 300 miles

v = 300 ÷ (3 + 3) = 50 mi/h