Question

a man walk 6km at 12km/h and return at 10 km/h.find speed

Answer 1

$\textbf {Hey there, here is the solution.}$

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Distance = 6km (Given)

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STEP 1: Find the time needed to walk there:

Speed = 12 km/h (given)

Time = Distance ÷ speed

Time taken to walk there= 6 ÷ 12

Time taken to walk there= 1/2 hour

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STEP 2: Find the time taken to return:

Speed = 10km/h (Given)

Time = Distance ÷ speed

Time taken to walk there= 6 ÷ 10

Time taken to walk there= 3/5 hour

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STEP 3: Find the total time:

Total time = 1/2 + 3/5 = 11/10 hour

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STEP 4: Find the total distance:

Total distance = 6 + 6 = 12km

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STEP 5: Find the average speed:

Speed = Distance ÷ Time

Speed = 12 ÷ 11/10

Speed = 10.9 km/h

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Answer: Speed = 10.9 km/h

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$\textbf {Cheers.}$

Answer 2

$\boxed{ \bold{ \underline{ \: speed \: } = \frac{distance \: }{time} }}$



Here,



$\large {\bold{ \underline{when \: going}}}$

$\bold{ \: s_{1} = \frac{ d_{1}}{ t_{1}} } \\ \\ \\ \bold{12 = \frac{6}{ t_{1} } \: \: \: hour} \\ \\ \\ \bold{ \: t_{1} = \frac{6}{12} \: \: \: hour} \\ \\ \\ \bold{ t_{1} = \frac{1}{2} \: \: \: hour}$







And





$\large{ \bold{ \underline{when \: returning}}}$




$\bold{s_{2} = \: \frac{ \: d_{2} }{\: \: t_{2}}} \\ \\ \\ \bold{10 = \frac{6}{ t_{2} } } \\ \\ \\ \bold{t_{2} = \frac{6}{10} \: \: hour } \\ \\ \\ \bold{ t_{2} = \frac{3}{5} hour}$








Hence,


$\bold{ speed = \frac{ d_{1} + d_{2} }{ t_{1} \: + t _{2}} } \\ \\ \\ \bold{ \: speed \: = \frac{12}{ \frac{1}{2} + \frac{3}{5} } } \\ \\ \\ \: \boxed{\bold{speed \: = \frac{120}{11} km /hr}}$