RRB Group-D Model Paper 20 with answers for online practice

Speed of the man from P to Q $\left({\mathit{S}}_1\right)$ = 5 km/hr
Speed of the man from Q to P $\left({\mathit{S}}_2\right)$ = 3 km/hr
Average speed = $2{\mathit{S}}_1\frac{{\mathit{S}}_2}{\left({\mathit{S}}_1+{\mathit{S}}_2\right)}$
= (2 × 5 × 3) / (5 + 3) km/hr
= 30 / 8 km/hr
= 15/4 km/hr
Hence, ‘None of the above’ is the correct answer.