If it takes 20 minute to get to the airport, and he wants to be there an hour and 5 minutes before his flight leaves, we have to subtract the time he leaves (9:50) by 1 hour and 5.
9:50 - 1 hour and 5 minutes.
9:50 - 65 minutes.
9:50 - 65 = 8:45.
Which means he must be at the airport at 8:45.
BUT,
The question is asking for the latest time that Quincy can LEAVE for the airport, which means it's 8:45 - 20 minutes, since it takes 20 minutes to get to the airport:
8:45 - 20 = 8:25
We have a right triangle with
a = one leg = 28
b = other leg = 21
c = hypotenuse = 5x
use the pythagorean theorem (a^2+b^2 = c^2) and solve for x
a^2+b^2 = c^2
28^2+21^2 = (5x)^2
784+441 = 25x^2
1225 = 25x^2
25x^2 = 1225
(25x^2)/25 = 1225/25
x^2 = 49
sqrt(x^2) = sqrt(49)
|x| = 7
x = 7 or x = -7
Since the hypotenuse has length 5x meters, this means
5x = 5*7 = 35
or
5x = 5(-7) = -35
Toss out the negative length as it makes no sense.
The only value of x is x = 7
Therefore the final answer is x = 7
The base fee ($30 & $20) are the independent variables.
An independent variable is a variable that does not depend on others
$8 & $10 depend on the number of hours so that is not the independent variable
