What is an equation i can use the find the rate of interest? "A = P(1 + rt)" is what i see when i look it up but how to i find "r" if that is what i am solving for to begin with?

For the chance to be team captain, the numbers 1-30 are put in a hat and you get two chances to pick a number, without replacement. which formula correctly shows how to find the probability that you choose the number 1 and then 2?