Car driver

The car driver is in town A and is scheduled to be in town B at a specified hour. If it travels at an average speed of 50km/h, it will arrive in city B 30 minutes later. But if he travels at an average speed of 70km/h, he would arrive half an hour earlier. Find the distance between cities A and B and the speed at which a driver would have to go to arrive at the specified hour.

Result

s =  175 km
v =  58.333 km/h

Solution:

s = 50*(t+30/60)
s = 70*(t-0.50)

60s-3000t = 1500
s-70t = -35

s = 175
t = 3

Calculated by our linear equations calculator.

$v=s/t=175/3 \doteq \dfrac{ 175 }{ 3 } \doteq 58.3333 \doteq 58.333 \ \text{km/h}$

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