I am stuck on a FIN 300 study note.

What rate of return should be required on the Bharti Airtel share, which has a Beta of 0.7, if the Rio Tinto share, which has a Beta of 1.1, returns 10% and is correctly valued, and the rate of a risk-free asset is 5%.

Our notes provide the solution, I don't understand this at all. Here is the solution the notes provide:

Risk premium: (10 % - 5%)/1.1 = 4.54%

k = 5% + 0.7 X 4.54% = 8.2%.

I don't understand any of this, can you please provide as much information as you can on how this was reached.

Thank you