Question

A train travels for seven hours, the first half of the distance at 60 km/ hr and the other half at 80 km/ hr. Find the total distance travelled

Answer 1

Answer:

The total distance travelled is 480 km.

Step-by-step explanation:

Let $x$ be  half of the distance. We have the relation between speed time and distance as,

$speed = \dfrac{distance}{time}$

It is given that during first half of the distance, train travels at a speed of $60 \ km/hr$ and second half at a speed of $80 \ km/hr$. Also total time taken is 7 hours.

Using the relation, we get time taken for first half of the distance as,

$time = \dfrac{x}{60}$

Time taken for second half of the distance is,

$time =\dfrac{x}{80}$

Since total time is 7 hours, we obtain the equation,

$\dfrac{x}{60}+\dfrac{x}{80}= 7\\\\\implies \dfrac{8x+6x}{480}=7 \\\\\implies 14x= 7\times 480= 3360\\\\\implies x= \dfrac{3360}{14} =240$

Thus half of the distance is 240 km. Hence total distance is 480km.