Question

A plane left 30 minutes later than the scheduled time and in order to reach its destination on 1500 km away in time it jas to increase its speed find its usual speed

Answer 1

according to me
speed=distance /time
and 30 min= 1/2 hour
so , 1500÷1/2
= 3000kmph

Answer 2

let scheduled time period be x

x-30/60 is the time of flight to cover same distance when plane has to make up

t1=x
t2=x-1/2
d1=d2=1500

s1=1500/x
s2=1500/x-0.5

s2(x-0.5)=s1*x

seems like something is missing in question to calculate usual speed


but if increase in speed part is required then it can simply be done 1500/0.5 hr=3000km/hr

this is the increase in speed than usual speed