Question

✼Question
➺A plan left 30 min late then it's scheduled time and in order to reach the distance 1500km away in time it had to increase its speed by100km/h from the usual speed find usual speed​

Answer 1

Answer:

Let the usual speed be  x km/hr.

Then, the speed taken  =(x+100) km/hr

Distance  =1500 km

Usual time  =

usual speed

distance

=

x

1500

 hrs

Time taken  =

x+100

1500

 hrs

It is given that  Time taken=Usual time−0.5 hrs

⇒

x

1500

−

x+100

1500

=

2

1

⇒

x(x+100)

1500(x+100)−1500x

=

2

1

⇒x

2

+100x=1500×100×2

⇒x

2

+100x−300000=0

⇒x=

2

−100±

100

2

+4×300000

=

2

−100±1100

=500 or−600

Since speed cannot be negative,  x=500 km/hr

∴  The usual speed of the plane is  500 km/hr.