Question

a car covers first half of the total distance with a speed of 36 km per hour at the second half with a speed of 54 km per hour find average speed of the car

Answer 1

Let the distance covered in first half be x
so second half would also be x

We know that time for first half = distance/speed

So time = x/36 hr

Second half time = x/54 hr


We know that average speed = total distance/total time

So average speed =
$\frac{x + x}{ \frac{x}{36} + \frac{x}{54 } } \\ \\ = > \frac{2x}{ \frac{3x + 2x}{108} } \\ \\ = > \frac{2x}{5x} \times 108 \\ = > \frac{2 \times 108}{5} \\ = 43.2$
hence AVG speed = 43.2km/hr

Hope it helps dear friend ☺️✌️