Question

two trains are traveling between city a and city b at a distance of 4000 kilometers (km). the regular train travels at a speed of 80 kilometers per hour (km/h). leaves at the same time on a parallel track and travels at 100 km/h. the formula for speed (s) is $s = \frac{d}{t}$ where s is speed, d is distance and t is time. how much express train arrive at city b?
10 hours
40 hours
50 hours
90 hours

Explanation:

Step1: Rearrange speed formula for time

We know $S = \frac{D}{T}$, so solving for $T$ gives $T = \frac{D}{S}$.

Step2: Plug in express train values

The distance $D = 4000$ km, speed $S = 100$ km/h. Substitute into the formula:
$T = \frac{4000}{100}$

Step3: Calculate the time

Perform the division: $T = 40$

Answer:

40 hours