A car travels 100 km at a speed of 60 km/h and returns with a speed of 40 km/h. Calculate speed for the hole journey? - IQ786

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A car travels 100 km at a speed of 60 km/h and returns with a speed of 40 km/h. Calculate speed for the hole journey?

A car travels 100 km at a speed of 60 km/h and returns with a speed of 40 km/h. Calculate speed for the hole journey?

48km/h

49km/h

28km/h

38km/h

Explanation

Using speed $= \frac{D i s t a n c e}{T i m e}$

$\Rightarrow T i m e = \frac{d i s t a n c e}{s p e e d}$
We have total time $= \frac{1 0 0}{6 0} + \frac{1 0 0}{4 0} = \frac{2 5}{6} H r$

Now, Average speed $= \frac{D i s t a n c e _{(t o t)}}{T i m e _{(t o t)}} = \frac{2 0 0}{\frac{2 5}{6}}$

$\Rightarrow$ Average spped $= \frac{1 2 0 0}{2 5} = 48 k$