Question

A man walks at a speed of 6 km/hr for 1 km and 8 km/hr
for the next 1 km. What is his average speed for the walk
of 2 km ?​

Answer 1

Answer:

Distance = 2km

time taken =

$\frac{1km}{6km} + \frac{1}{8}$

$= > \: \frac{7}{24} hr.$

average speed,

$\frac{2 \times 24}{7} = > \frac{48}{7} km$

$= > 7km$

Answer 2

Case 1

Speed = 6km/h

distance = 1 km

Time = distance / speed = 1/6 h

case 2

Speed = 8 km/h

Distance = 1 km

Time = distance / speed = 1/8 h

Average speed = Total distance / total time taken

= 1 + 1 / 1/6 + 1/8

= 2 / (4 + 3) /24

= 2 / (7/24) = 2 x 24 / 7 = 48/7 = 6.85 km/h