The difference of 7 and a number n

Evaluate the expression for the given value of the variable 7a - 4a for a =8

One positive number is 9 more than twice another. if their product is 95, find the numbers

Peter applied to an accounting firm and a consulting firm. he knows that 30% of similarly qualified applicants receive job offers from the accounting firm, while only 20% of similarly qualified applicants receive job offers from the consulting firm. assume that receiving an offer from one firm is independent of receiving an offer from the other. what is the probability that both firms offer peter a job?