Question

Starts from his home at 25 km per hr and reach school at 20 minutes late.if he would have walked at 40 kilometer per hour he would have reached to 10 minutes early.find the distance between the school and home

Answer 1

Answer:

33⅓

Step-by-step explanation:

let the distance be x

let the time be t

by the speed of 25

D/S=T

x/25=t+1/3. (20mins=1/3hr)

by the speed of 40

D/S=T

x/40=t-1/6. (10mins=1/6hr)

subtracting eq2 from eq1,

x/25 - x/40=(t+1/3)-(t-1/6)

8x/200 - 5x/200= t+1/3-t+1/6

3x/200= 1/3+1/6

3x/200= 3/6

x/200=1/6

x= 200/6

x= 33⅓

........666.........

Answer 2

Answer:

The distance of between the school and home will be equal to (200/6)km.

Step-by-step explanation:

Consider the distance between school and home is x.

Time taken when speed 25km/hr is $=\frac{x}{25}$

Time taken when speed 40km/hr is $=\frac{x}{40}$

The difference in time will be $=[(t+20)-(t-10)]min$

                                              $=(20+10)min$

                                              $=\frac{30}{60}hr=\frac{1}{2}hr$

From the question:

⇒       $\frac{x}{25} -\frac{x}{40} =\frac{1}{2}$

⇒       $\frac{x}{5} -\frac{x}{8} =\frac{5}{2}$

⇒      $\frac{8x-5x}{40}=\frac{5}{2}$

⇒      $2(3x)=200$

⇒       $6x=200$

∴        $x=\frac{200}{6}$

Therefore the distance is equal to (200/6)km or 33.33km.