Question

A car travels 30km at a uniform speed of 40 km/h and next 30km at a uniform speed of 20km/h . Find it's average speed​

Answer 1

answer is 2.66

Explanation:

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Answer 2

$\large\sf\underline\blue{Given \: :- }$

• A car travels 30km at a uniform speed of 40 km/h.
• next 30km at a uniform speed of 20km/h.

$\large\sf\underline\blue{To \: find \: :- }$

• Find it's average speed ?

$\large\sf\underline\blue{Solution \: :- }$

$\large\bf\underline{Using \: formula :- }$

${\large{\underline{\boxed{\sf{\red{Speed = \frac{Distance}{ Time} }}}}}}$

By first condition,

If Speed = Distance/Time

Also we write time = Distance/Speed

$\sf\implies{time = \frac{distance}{speed} } \\ \sf\implies{time = \frac{30}{40 } = \frac{3}{4} } \\ \sf\implies{time = 45min} \: \: \:$

By second condition,

$\sf\implies{time = \frac{30}{20} = \frac{3}{2} } \\ \sf\implies{time = 90min} \: \: \:$

Now,

Finding speed

Speed = Total Distance / Total time

Total distance = 30 + 30 = 60

Total time = 135min = 2.25 hour

$\sf\implies{average \: speed = \frac{60}{2.25} = 26.66km/h}$

${\large{\underline{\boxed{\sf{\red{Average \: Speed = 26.66km/h}}}}}}$

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