The speed of the train going from Nagpur to Allahabad is 100 km/h while when coming back from Allahabad to Nagpur, its speed is 150 km/h. find the average speed during whole journey.
A. 125 km/hr
B. 75 km/hr
C. 135 km/hr
D. 120 km/hr
Show Answer
Answer-D
Solution-
Solution(By Apex Team)
$\begin{array}{l} \text { Average speed, }\\ =\Large\frac{2 \times x \times y}{x+y}\\ =\Large\frac{2 \times 100 \times 150}{100+150}\\ =\Large\frac{200 \times 150}{250}\\ =120 \mathrm{~km} / \mathrm{hr} \end{array}$
