Answer:
RA = 20.45 Km
Step-by-step explanation:
We need to define our variables

For
(Pulse repetition frequency)
And
(Pulse repeition time)
We proceed to calculate the Maximum unambiguous range of radar,

Where
Pulse Width.
We do not have the Pulse Width, so we can think that can be omited.

converting the miles to kilometers of our target, we have,

So the number of the pulses can be calculated as follow,

Therefore, N=3.
Presently,X MOD Y

Evident range of target,
![RA = R MOD [(C*PRI)/(2)]](https://img.qammunity.org/2020/formulas/engineering/college/b4t51yrpvikoap9m8ugfdt9v71z7hdsohn.png)
![RA = 80.45 MOD [((3x108x2x10^(-4))/(2)) *10^(-3)]\\ RA = 80.45 MOD 30\\ RA = 20.45 Km](https://img.qammunity.org/2020/formulas/engineering/college/r0n5gnt00471nltv0k4is0wc0tcecaw8jo.png)