Question

A car covers a certain distance travelling at a speed of 60 kmph and returns to the starting point at a speed of 40 kmph. Find the average speed for the entire journey.​

Answer 1

Step-by-step explanation:

A man covers a certain distance by car at speed 60 km/hr and returns at speed of 40 km/hr. ... =2×60×4060+40=4800100 = 48 kmph.

Answer 2

$\: \sf \huge \underline \red{correct \: Question : }$

• A man covers a certain distance by car at speed of 60 km/hr and returns at speed of 40 km/hr .find his average speed for his whole journey.

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$\implies \huge \sf \underline \blue{Answer : }$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \bf{ \boxed{ \underline{ \underline{ \purple{ \tt{48 \: kmph \: }}}}}}$

$\implies \huge \sf \underline \pink{To \: find : }$

• average speed

$\implies \huge\sf \underline \purple{solution}$

$\: \: \: \sf \underline{we \: know \: that \: formula \: of \: average \: speed}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \bf{ \boxed{ \underline{ \underline{ \red{ \sf{Average \: speed = \dfrac{2xy}{x + y \: }}}}}}}$

so,

• x is 60
• y is 40

$\: \: \: \sf \underline{According \: to \: formula}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \bf{ \boxed{ \underline{ \underline{ \red{ \sf{Average \: speed = \dfrac{2xy}{x + y \: }}}}}}}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \sf \blue{↝ \: = \dfrac{2 \times 60 \times 40}{60 + 40}}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \sf \blue{↝ \: = \dfrac{4800}{100}}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \sf \blue{↝ \: 48 \: kmph}$

$\sf \therefore \underline \orange{Average \: speed \: is \: 48kmph}$