Question

A truck covers a distance of 3 km at a certain speed and then covers another 4 km at a speed 20 km/hr more. If the truck takes 10 min to cover the total distance, find the speed of the truck?

Answer 1

The speed is 32.96 kmph.

Step-by-step explanation:

• We assume that the truck covers the distance of 3 km at the speed x kmph.

• It is given that the truck covers the distance of 4 km at a speed 20 kmph more.

• It means that truck covered the distance of 4 km at the speed (x + 20) kmph.

• Also, it is given that the truck takes total 10 minutes or 1/6 hours in complete journey.

Now, we write as;

• Time taken to cover 3 km distance + time taken to cover 4 km distance = $\dfrac{1}{6}$ hours

$\dfrac{3}{x} + \dfrac{4}{x + 20} = \dfrac{1}{6}$

By simplifying it, we get as,

• x = $\dfrac{22 \pm 43.93}{2}$

        x = 32.96 kmph, -10.96 kmph

So, x = 32.96 kmph is the answer.