A motor boat left point A to point B at a speed of 12 km / h. 4 hours later a second

A motor boat left point A to point B at a speed of 12 km / h. 4 hours later a second motor boat followed her, the speed of which is 14 km / h. Find the distance between points A and B, if both motor boats came to point B at the same time …

Time is found by the formula:

t = S: v,
where t is time, S is distance, v is speed.

Let the distance between points A and B be equal to “x” km.

The first boat will sail the distance between points in “x / 12” hours.

The second boat will sail the same distance in “x / 14” hours.

The second boat will spend 4 hours less for the whole journey.

Knowing this, we can make the equation:

x / 12 = x / 14 + 4;

x / 12 = x / 14 + (4 * 14) / 14;

x / 12 = (x + 56) / 14;

14x = 12x + 56 * 12;

14x – 12x = 672;

2x = 672;

x = 336 (km) distance between points.