1,000 miles is the total length of the trip
(AB)^2 + (2 m)^2 = (8 m)^2, or
(AB)^2 + 4 m^2 = 64 m^2, or (AB)^2 = 60 m^2.
Taking the square root of both sides, (length of AB) = + 2sqrt(15) (answer)
Multiply the investment fraction by the corresponding return, and add the products. The given fractions add to 59%, so the remainder is 41%. (The total of the fractions is 100%—all of the portfolio.)
... 0.43*9.1% + 0.16*16.7% + 0.41*11.4%
... = 3.913% + 2.672% + 4.674% = 11.259%
When the base is greater than 1, the value approaches zero as the exponent goes to -∞. When the base is less than 1, the value approaches zero as the exponent goes to ∞. Whatever additions or factors you have that modify the exponential term will modify the asymptote accordingly.