#### Answer

$y=5e^{-0.68t}$

#### Work Step by Step

$(0, 5)$ lies on the curve.
Thus, $$5 = Ce^{k.0}$$
Or, $$C=5$$
$(5, \frac{1}{6})$ lies on the curve.
Thus, $$\frac{1}{6} = 5e^{5k}$$
Or, $$e^{5k}=\frac{1}{30}$$ $$k = \frac{\ln(1/30)}{5} = -0.68$$
So, the function is $$y=5e^{-0.68t}$$