Answer:
5 hours
Explanation:
From the question, we are told that:
Time required to drive a fixed distance varies inversely as the Speed
T ∝ 1/S
k = proportionality constant hence,
T =k × 1/S
T = k/S
Step 1
Find k
It takes 2 hr at a speed of 200 km/h to drive a fixed distance
T = 2 hours, S = 200km/h
T = k/S
2 = k / 200
k = 2 × 200
k = 400
Step 2
How long will it take to drive the same distance at a speed of 80 km/h?
S = 80km/h
T = k/S
k = 400
T = 400/80
T = 5
Therefore, it takes 5 hours to drive the same distance at a speed of 80km/hr