Question

Hi Class 11th

A car starts from point A and then Travels to point B with the speed of 20 km per hour and returns from point B to A with the speed of 30 km per hour. Calculate the average speed.::..::.

Answer 1

$\boxed{\boxed{\boxed{\purple{Hello \:Dear\:Students}}}}$

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✴Let the distance between the two points A and B be x m .

✴When the car moves from point A to B . Let the time taken be T1.

✴When the car returns Let the time taken be T2.

$\textbf{For\:A\:to\:B,}$Speed = $\frac {Distance}{Time}$

$\: \: \: \: \: 20 \: = \: \frac{x}{t1}$

$\: \: \: \: \:t1 \: = \: \frac{x}{20}$

$\textbf{For\:B\:to\:A,}$ Speed = $\frac {Distance}{Time}$

$\: \: \: \: \: 30 \: = \: \frac{x}{t2}$

$\: \: \: \: \: t2 \: = \: \frac{x}{30}$

$\textbf{\boxed{Average\:Speed\:of\:Car:-}}$

$= \:\frac {T.dis}{T.time}$

$= \: \frac{x + x}{t1 + t2}$

$= \: \frac{2x}{ \frac{x}{20} + \frac{x}{30} }$

$= \: \frac{2x}{x \binom {1}{20} + \binom{1}{30} }$


$= \: \frac{2 \times 600}{50}$


$=\:24km/h\:\:\:\:\:\:\boxed{ans}$

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Hope this helps. . . . . . ❤❤