Serious how to calculate rate of investment?

I want to ask how to calculate:

yesterday I dump $50k buying gold.(capitalizing on EU crisis)
today I sold off at the peak.
profit is $1350

1350/50000 x1oo = 2.7% in 2 days.

then my insurance friend tell me this.
aiyo 2.7% is nothing loud to shout about.
nsf and some bank can get 2% interest rate by saving.
you just earn 0.7% more than them

I want to ask:
I reap 2.7% in 2 days.
how to convert rate of investment profit into a year since bank and nsf is base of 365days 1 year?

Your insurance friend is trying to get you to buy insurance.

2 pct in a day is damn good. Ask your friend if he could produce a return of 2 pct a month?