After working for 25 years as personal fitness trainers while raising their​ kids, three sisters cashed in a total of ​$80 comma 000 in bonds and decided to open a​ small, neighborhood fitness center. they spent the ​$80 comma 000 on exercise​ equipment, advertising, computer​ equipment, and other furnishings for the business. for the next 3​ years, they took in ​$150 comma 000 in revenue each​ year, paid themselves ​$35 comma 000 annually​ each, and rented a space in a strip mall for ​$22 comma 000 per year. before the​ investment, their ​$80 comma 000 in bonds were earning interest at a rate of 15 percent. are they now earning economic​ profits? explain​ your answer.