Your university radio stawon has a 5.0-kw radio transmixer that broadcasts uniformly in all direcwons; listeners within 15 km have reliable recepwon. you want to increase the power to double that range. what should be the new power?

The received signal strength decreases as the square of the distance from the transmixer. Right now, people who are twice as far away get 1/4 as much signal. So if you want to give them the full shot, you need to increase your power output by 4 times, to 20 Kw.