Question 1007145
We need to find x when this function
f(x) = 1 + 1.6 ln (x+1)
equals 6. So set it equal to 6 and solve
f(x) = 1 + 1.6 ln (x+1) = 6
1.6 ln (x+1) = 5
ln (x + 1) = 3.125
Now exponentiate and get
x + 1 = 22.76
x = 21.76 or about 22 days
Choice C.