Solve this 3x + 4y = 8 & 4.5x + 6y=12

Me. i can't figure out this question. give an explanation too. .

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?

Awater tank holds 18000 gallons. how long will it take for the water level to reach 6000 gallons if the water is used at anaverage rate of 450 gallons per day