From point A to point B, the distance between which is 50 km, a motorist and a cyclist left at the same time.
From point A to point B, the distance between which is 50 km, a motorist and a cyclist left at the same time. It is known that a motorist travels 65 km more per hour than a cyclist. Determine the speed of the cyclist if it is known that he arrived at point B 4 hours and 20 minutes later than the motorist.
According to the conditions of the problem, the speed of the car is 65 km / h more than the speed of the cyclist, then the speed of the cyclist is denoted by X, and the speed of the car is X + 65. Knowing the time at which the cyclist arrived later than the motorist, we make the equation: 50 / (X + 65) + 13/3 = 50 / X. Having got rid of the denominators, we get the quadratic equation 13X ^ 2 + 845X – 9750 = 0. Solving this equation, we get two values of X (-75 and 10). Since the speed cannot be negative, the correct answer is 10 km / h