Question

A cyclist pedals home to college at a speed of 8km per hour and back at 12 Km per hour. Find average speed.( HIint : Find the harmonic mean of 8 12)

Answer 1

Step-by-step explanation:

Let the distance of his office be xkm and thr right time to reach office be t min

Time taken to reach office at 8km/hr =

60

t+2.5

=

8

x

(i)

Time taken to reach office at 10km/hr =

60

x−5

=

10

x

(ii)

Subtracting (ii) from (i) we get,

60

7.5

=

8

x

−

10

x

60

7.5

=

40

5x−4x

x=

60

7.5×40

x=5km