Question

3. A motorist travels one hour at an average speed of 45 kmph and the next hour at an
average speed
of 65 kmph. Then what is his average speed?​

Answer 1

Answer

Average Speed = 55 km/h

Given

A motorist travels one hour at an average speed of 45 kmph and the next hour at an  average speed  of 65 kmph

To Find

Average Speed

Concept Used

Speed :

It is defined as distance travelled per unit time

Average Speed

It is defined as total distance travelled per unit time

$\bf A_{Speed}=\dfrac{Total\ distance}{Total\ time}\ \;\; \bigstar$

Solution

Case - 1 :

Speed , S = 45 km/h

Time , t = 1 h

Distance , d = ? km

Apply formula ,

$\implies \rm S=\dfrac{d}{t}\\\\\implies \rm 45=\dfrac{d}{1}\\\\\implies \rm d=45\ km$

Case - 2 :

Speed , S = 65 km/h

Time , t = 1 h

Distance , d = ? km

Apply formula ,

$\implies \rm S=\dfrac{d}{t}\\\\\implies \rm 65=\dfrac{d}{1}\\\\\implies \rm d=65\ km$

_____________________

Apply formula for Average speed ,

$\implies \rm A_{Speed}=\dfrac{Total\ distance}{Total\ time}\\\\\implies \rm A_{Speed}=\dfrac{45+65}{1+1}\\\\\implies \rm A_{Speed}=\dfrac{110}{2}\\\\\implies \rm A_{Speed}=55\ km/h$

Answer 2

hi

here is ur answer

is this clear for u guys?