Answer:
Subtract 6,900 from 8,500 to get the highest number of tickets that can still be sold which is 1,600.
Call (F) the age of the father and (J) the age of Julio
The F & J are related in this way: F=4J
Now you have a restriction in the form of inequality: The sum of both ages has to be greater or equal than 55.
Algebraically that is: F + J ≥ 55
You can substitute F with 4J to find the solution for J:
4J + J ≥ 55
5J ≥ 55
Now divide both sides by 5
5J/5 ≥ 55/5
J ≥ 11
That Imposes a lower boundary for the value of J of 11, meaning that the youngest age of Julio can be 11
Remember that there is 100 centimeters in a meter, and 1000 meters in a kilometer. If you multiply both values together (so you have a conversion of centimeters to kilometers) you get 100,000. Therefore, 100,000 centimeters makes a kilometer. Divide 320,000 by 100,000 and you get 3.2. Therefore, a centimeter would represent 3.2 kilometers.
First we will calculate the distance AB.

If C is 5/9 of the distance, mathematically speaking that means:

R: The coordonate of C is 15.