Answer
AM
$\lambda_{min}\approx 190 m$
$\lambda_{max}\approx 550 m$
FM
$\lambda_{min}\approx 2.8 m$
$\lambda_{max}\approx 3.4 m$
Work Step by Step
The wave speed is given by $v=\lambda f$. The minimum wavelength corresponds to the maximum frequency, and vice versa.
First, AM radio.
$$\lambda_{min}=\frac{v}{f_{max}}=\frac{3.0 \times 10^8 m/s}{1600 \times 10^3 Hz}\approx 190 m$$
$$\lambda_{max}=\frac{v}{f_{min}}=\frac{3.0 \times 10^8 m/s}{550 \times 10^3 Hz}\approx 550 m$$
Next, FM radio.
$$\lambda_{min}=\frac{v}{f_{max}}=\frac{3.00 \times 10^8 m/s}{108 \times 10^6 Hz}\approx 2.8 m$$
$$\lambda_{max}=\frac{v}{f_{min}}=\frac{3.00 \times 10^8 m/s}{88 \times 10^6 Hz}\approx 3.4 m$$