For this we simply divide the total ft. by the ft. in a mile
F(x) = √(5x + 7)
g(x) = √(5x - 7)
(f + g)(x) = f(x) + g(x)
(f + g)(x) = √(5x + 7) + √(5x - 7)
Answer: C)
Well... all u have to do is 85 divided by 4 which equals 21.25..... unless there is another part of the question!!
2.25h(60m/hr)(1/3)=45m
So Rick spends 45 minutes studying math per night.