Javed traveled from home to office at an average speed of 20 mph. Then he drove back from the office at an average speed of 30 mph. If he spent a total of 3 hours traveling and he took the same road each way, what is the total distance (in miles) that Javed travelled?

Question: Javed traveled from home to office at an average speed of 20 mph. Then he drove back from the office at an average speed of 30 mph. If he spent a total of 3 hours traveling and he took the same road each way, what is the total distance (in miles) that Javed travelled?

Solution:
Let distance from home to office = d miles

Now,
t₁ = d/20 & t₂ = d/30
∴ Total time t = t₁ + t₂
= (d/20) + (d/30)
= (3d + 2d)/60
= 5d/60
= (d/12) hours

ATQ,
d/12 = 3
⇒ d = 36

∴ Total distance that Javed travelled = 36 + 36 = 72 miles