I need this explained in detail so that I can complete this with a paper and pen and a regular calculator, not a financial one. In detail form, please explain the step by step process that is used to find the answer.

You have just won $50 million in a lottery and are offered two options: receive $40.84 million today or receive $5 million per year for the next 10 years. At what interest rate are you indifferent to the choice between the two options?