Question

the distance between ahmedabad and vadodara is 100 km. a scooterist travels it with an average speed of 50 km /hr . if he travels first 60 km at a uniform speed of 45 km /hr . what will be it's speed for the remaining distance​

Answer 1

Average speed = total distance / total time

Let the average speed be v(av) =50 km/h

As we know he covers 60 km with speed 45km/h

Let the speed he covers the distance of 100 - 60 = 40 m with speed v2

Now,

$v(av) = \frac{100}{ \frac{60}{45} + \frac{40}{v2} }$

$50= \frac{100}{ (\frac{v2.60 + 1800}{45v2}) }$

$50 = (\frac{100.45v2}{60v2 + 1800} )$

3000v2 + 90000 = 4500v2

90000 = v2(4500-3000)

90000 = 1500v2

900 = 15v2

= 60 km/hr