Numerical Methods: Euler to Runge–Kutta · Challenge problem

The stiff decay problem $y' = -40y$, $y(0) = 1$ (exact solution $e^{-40t}$) is integrated by the trapezoidal method $y_{n+1} = y_n + \dfrac{h}{2}\left(f(t_n, y_n) + f(t_{n+1}, y_{n+1})\right)$ with $h = \dfrac{1}{10}$. What is the computed estimate of $y(0.3)$? Express your answer as a common fraction.