Two cars are driving towards each other. The speed of one of them is 75 km / h, which is 5/6 of the speed of the second.

Two cars are driving towards each other. The speed of one of them is 75 km / h, which is 5/6 of the speed of the second. The second car left 1.6 hours later than the first. How many hours after the departure of the second car will they meet if the initial distance between them was 615 km?

Let’s calculate the speed of the second car:
75: 5/6 = 75 * 6/5 = 90 km / h;
Let’s denote the time that the second car drove before the meeting, after x hours and compose the equation:
(1.6 + x) * 75 + x * 90 = 615;
120 + x * 75 + x * 90 = 615;
(75 + 90) * x = 615 – 120;
165 * x = 495;
x = 495/165 = 3;
Answer: they will meet 3 hours after the second car leaves.