Question

A train travels at a speed of 10m/s for half the journey and at a speed of 40m/s for the rest of the journey. Find the average speed of the whole journey in m/s

Answer 1

please please refer the attachment for for better understanding

S1=s/2

V1=10m/s

T1=S1/V1

T1=S/20

S2=S/2

V2=40m/s

T2=S2/V2

T1=S/80

$average \: speed = \frac{total \: distance}{total \: time} \\ average \: speed = \frac{s}{t1 + t2} average \: speed = \frac{s}{s( \frac{1}{20} + \frac{1}{80} } \\ average \: speed = \frac{1}{ \frac{5}{80} } \\ average \: speed = \frac{80}{5} = 16 \frac{m}{s}$

I hope this helps