Final answer:
Alice travels 3 times faster than Brenda. To find their rates of travel, we can set up an equation using the distance formula and solve for Brenda's rate of travel. Brenda's rate of travel is 6 mph and Alice's rate of travel is 18 mph.
Step-by-step explanation:
In this problem, Alice and Brenda are traveling in opposite directions and are 720 miles apart after 7.5 hours. We need to find their rates of travel. Let's assume Brenda's rate of travel is x mph, then Alice's rate of travel will be 3x mph since Alice travels 3 times faster than Brenda.
To find their rates of travel, we can use the formula: Distance = Rate x Time.
Since they are 720 miles apart and have traveled for 7.5 hours, we can set up the equation 720 = (x + 3x) * 7.5.
Simplifying the equation, we get 720 = 4x * 7.5. Dividing both sides by 30 gives us x = 6.
Therefore, Brenda's rate of travel is 6 mph and Alice's rate of travel is 3x, which is -
= 3 * 6 = 18 mph.