Answer:
yea that makes sense
It literally tells you how to do it
Is it some kind of proof tho? Like the math makes sense but like I've never heard of this thing.
Answer:
An irrational number is a real number that can't be written as a fraction.
Ex. 
A rational number is a real number such as a whole number, fraaction, decimal, or integer.
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.
Let's say that the price of each normal cookie is n.
The equation would then be 7(n - .75)=2.80.
Use distributive property, getting 7n - 5.25=2.80.
Add 5.25 to each side of the equation, getting 7n=8.05.
Divide 7 from both sides of the equation, getting n=1.15.
The larger number is 6 and the smaller one is 2.