Question

While arriving jayant travels 30km with uniform speed of 40km/h and next 30 km with uniform speed of 20km/h. Find average speed

Answer 1

Case 1
Speed = 40km/hr
Distance = 30 km
:time = D/S
= 30/40 =3/4hr
Case 2
Speed = 20km/hr
Distance = 30 km
Time= 30/20 = 3/2hr
Now,
Total time = 3/4 + 3/2
= 9/4hr
Average speed = total distance / total
time
= (30 + 30 )÷9/4
= 26.6km/hr

Answer 2

Answer:

Average speed, v = 26.7 km/h

Explanation:

Total distance, d = 30 km + 30 km = 60 km

While arriving Jayant travels 30 km with uniform speed of 40 km/h and next 30 km with uniform speed of 20 km/h.

Time, $t=\dfrac{d}{v}$

$t_1=\dfrac{30\ km}{40\ km/h}=0.75\ h$

$t_2=\dfrac{30\ km}{20\ km/h}=1.5\ h$

Average speed, $v=\dfrac{total\ distance}{total\ time}$

$v=\dfrac{60\ km}{(0.75+1.5)\ h}$

v = 26.7 km/h

Hence, the average speed of Jayant is 26.7 km/h.

Hence, this is the required solution.