The distance between settlements A and B is 650 km. A bus departed from point A at a speed of 40 km / h.

The distance between settlements A and B is 650 km. A bus departed from point A at a speed of 40 km / h. After 30 minutes, another bus left point B towards him, the speed of which was 10% higher. How long after the departure of the first bus will they meet?

Let’s determine the average speed of the second bus:
40 + 40 * 10/100 = 44.
Let us denote by the variable x the time that the first bus spent on the way before meeting the second bus.
Then, the first bus covered a distance of 40 km before the meeting, and the second bus covered a distance of 44 (x – 0.5) before their meeting.
Let’s make an equation and determine what time the first bus was on the way before the meeting:
40x + 44 (x – 0.5) = 650;
84x = 672;
x = 8.
Answer: Before the meeting, the first bus had been on the road for 8 hours.