Question

A car covers 30 km at a uniform speed of 30 km/h. If it covers next 90 km at the uniform speed of 60
km/h. find the average speed of the car in the entire journey.
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Answer 1

$\bigstar\large\underline{\mathtt{ Solution : }}$

• Distance (d) = 30 km
• Speed (s) = 30 km / hr

we know that ,

➽ s = d / t

here ,

• s = speed
• d = distance
• t = time

➝ t = d / s

➝ t = 30 / 30

➝ t = 1 hr

__________

• Distance (d') = 90 km
• Speed (s') = 60 km / hr

we know that ,

➽ s = d / t

here ,

s = speed

d = distance

t = time

➝ t = d' / s '

➝ t = 90 / 60

➝ t = 1.5 hr

__________

Average speed is given by the formula ,

= total distance / total time

= d + d ' / t + t '

= 30 + 90 / 1 + 1.5

= 120 / 2.5

= 48 km / hr

The average speed of the car is 48 km / hr

Answer 2

Explanation:

distance (d) =30km

speed (s) =30km/gr