. Mark takes out a loan for $30000 to add on a new exam room for his practice. Now, the bank charges 5.4% interest.Question: how much interest will he pay in 5 years?=> 30 000 dollars = the money he owe=> 5.4 = 5.4% / 100% = .054Now, let's solve for the answer=> 30 000 dollars * 0.054 = 1 620 dollars. is the interest for 1 year.let's solve for 5 years.=> 1 620 dollars * 5 = 8 100 dollars'