# SNR when calculating noise

I am trying to solve a few example questions relating to input voltage and input noise for the following questions.

and

I understand that I need to calculate the maximum noise voltage acceptable for the required SNR using the equation, SNR = 20log(Signal/Noise).

The thing I am having trouble understanding is for the first question, in the solutions the input noise voltage is calculated using:

Whilst in the solution for the second problem it uses:

I cannot see any difference in the question as to why one would be squared and the other not. Thanks in advance.