A man walks for 5 km/hr for 1 km and 7 km/hr for next 1 km. What is his average speed for the walk of 2 km?
-5.8 km/hr
-6.0 km/hr
-2.0 km/hr
-1.0 km/hr
Thank you very much!!
Btw the answers I gave above are positive values, not negative values. Sorry for any confusion.
d1 = V1*t1 = 1 km.
t1 = 1/V1 = 1/5 = 0.20 h.
t2 = 1/V2 = 1/7 = 0.143 s.
V=d/(t1+t2)=2km/(0.20+0.143)h=5.8 km/h.
To find the average speed for the entire walk of 2 km, you need to calculate the total time taken for the walk and then divide the total distance by the total time.
Let's break down the walk into two parts:
For the first kilometer at a speed of 5 km/hr, the time taken can be calculated as 1 km / 5 km/hr = 0.2 hours.
For the second kilometer at a speed of 7 km/hr, the time taken can be calculated as 1 km / 7 km/hr = 0.1429 hours (rounded to 4 decimal places).
Now, add the times taken for both parts: 0.2 hours + 0.1429 hours = 0.3429 hours (rounded to 4 decimal places).
Finally, calculate the average speed by dividing the total distance (2 km) by the total time (0.3429 hours):
Average speed = 2 km / 0.3429 hours ≈ 5.8301 km/hr
Rounding to one decimal place, the average speed is approximately 5.8 km/hr.
Therefore, the correct answer is -5.8 km/hr.