If oil costing $22.50/barrel is combined with oil costing $35/barrel, how much of each is required to create 1250 barrels costing $27.50/barrel

As voters exit the polls, you ask a representative random sample of voters if they voted for a proposition. if the true percentage of voters who vote for the proposition is 63%, what is the probability that, in your sample, exactly 5 do not voted for the proposition before 2 voted for the proposition? the probability is