Vikas can cover a distance in 1 hr 24 min by covering 2/3 of the distance at 4 kmph and the rest at 5 kmph the total distance is?

6 km

Let the total distance travelled be = x km

Time = 1 + \(\frac{24}{60}\) = 1 + \(\frac{2}{5}\) =  \(\frac{7}{5}\)

We know that, 

Speed = \(\frac{ Distance}{ Time}\)

Time =  \(\frac{ Distance}{Speed}\)

\(\frac{7}{5}\) = \(\frac{ 2/3 x }{4}\) + \(\frac{ 1/3 x }{5}\)

\(\frac{7}{5}\) = \(\frac{ 2x }{12}\) + \(\frac{ x }{15}\)

\(\frac{7}{5}\) = \(\frac{\text {10x + 4x }}{60}\) 

\(\frac{7}{5}\) = \(\frac{\text {14x }}{60}\) 

x = \(\frac{\text { 7 x 60}}{\text{14 x 5}}\) 

x = 6 km