Answer:
Step-by-step explanation:
The slope of a line that is perpendicular to another will have an opposite-reciprocal slope. So, if the slope was -2, then the perpendicular slope would be 
.
This is written in slope-intercept form:
m is the slope and b is the y-intercept. Find the opposite-reciprocal of the slope, -5:
Now we need to find the y-intercept. For this, substitute the given points for its appropriate value:
Solve for b:
Simplify multiplication:
Insert:
Subtract b from both sides:
Subtract 3 from both sides:
Simplify subtraction:
Insert:
Multiply both sides by - 1 to simplify b (it can be seen as -1b):
Insert:
:Done
The important formula to this problem is
or
Now, the speed of the car is 70 km/h, and the speed of the truck is 50 km/h. It will take the two vehicles the same amount of time to meet since they both left at the same time. So, since distance equals rate times time, and t = time:
the distance of the car = 70t
the distance of the truck = 50t
Because they both left in opposite directions, and the towns are 420 kilometers apart, the equation for this would be
We now solve the equation.
It will take the vehicles 3 and a half hours to meet. Since we're looking for the time, 3 and a half hours from 10:00 AM is 1:30 PM.
So, the car and the truck will pass each other at 1:30 PM.
