Question

a train is moving 100km/h it takes 18min to reach a station what should be it's speed if the train wants to reach the station in 15 min

Answer 1

$d1 = s1 \times t1 = 100 km {h}^{ - 1} \times \frac{18}{60}h = 30km \\d2 = d1 = s2 \times t2 \\ 30 = \frac{15}{60} \times s2 \\ s2 = \frac{30 \times 60}{15} = 120km {h}^{ - 1}$

Answer 2

120km/hr

Speed=100km/hr

Time=18mins=18/60hrs

Distance=speed *time

=100*18/60=30km

Now we know the distance

Time=15mins=15/60 hrs

Speed=Distance/time

=30/15/60

=30*60/15=120km/hr