Answer:
637 km/h, not reasonable
Explanation:
Total average speed = 91 km/h
Average speed of first half, v1 = 49 km/h
Let the average speed for the next half is v2.
Let the total distance is 2s.
Time taken for first half of the journey, t1 = s / v1 = s / 49
Time take for the next half of the journey, t2 = s / v2
The average speed is defined as the total distance traveled to the total time taken
[tex]91=\frac{2s}{\frac{s}{49}+\frac{s}{v_{2}}}[/tex]
[tex]\frac{s}{49}+\frac{s}{v_{2}}=\frac{2s}{91}[/tex]
[tex]\frac{1}{v_{2}}=\frac{2}{91}-\frac{1}{49}[/tex]
[tex]\frac{1}{v_{2}}=\frac{7}{4459}
v2 = 637 km/h
This is very high speed which is not reasonable.
