Answer:
Step-by-step explanation:
Temperature needs to fall by 3 degrees
Your answer would be -11.
I'm going to assume the rate, 3.9%, is for one year.
7550 * 3.9 * 6 = $176, 670 is the simple interest earned in 6 years with a rate of 3.9% per year.
Since you have the formula, why don't you do it yourself?