Hello I need help with my business calculus hw​

Mr. smith recently faced a choice between being (a) an economics profes-sor, which pays $60,000/yr, or (b) a safari leader, which pays $50,000/yr. after careful deliberation, smith took the safari job, but it was a close call. "for a dollar more," he said, "i'd have gone the other way."now smith's brother-in-law approaches him with a business proposition. the terms are as follows: - smith must resign his safari job to work full-time in his brother-in-law's business.- smith must give his brother-in-law an interest-free loan of $100,000, which will be repaid in full if and when smith leaves the business. (smith currently has much more than $100,000 in the the business will pay smith a salary of $70,000/yr. he will receive no other payment from the business.the interest rate is 10 percent per year. apart from salary considerations, smith feels that working in the business would be just as enjoyable as being an economics professor. for simplicity, assume there is no uncertainty regarding either smith's salary in the proposed business or the security of his monetary investment in it. should smith join his brother-in-law and, if so, how small would smith's salary from the business have to be to make it not worthwhile for him to join? if not, how large would smith's salary from the business have to be to make it worthwhile for him to join?

Aborrower takes out a 30-year adjustable rate mortgage loan for $200,000 with monthly payments. the first two years of the loan have a "teaser" rate of 4%, after that, the rate can reset with a 5% annual payment cap. on the reset date, the composite rate is 6%. what would the year 3 monthly payment be?

Alarge tank is filled to capacity with 500 gallons of pure water. brine containing 2 pounds of salt per gallon is pumped into the tank at a rate of 5 gal/min. the well-mixed solution is pumped out at the same rate. find the number a(t) of pounds of salt in the tank at time t.