You and your best friend want to go on a cruise to alaska. you have done some research and discovered that it will cost $2800 for the plane tickets, all-inclusive cruise fare, and souvenirs. you have already saved $1900. if you invest this money in a savings account with a 2.5% interest rate compounded annually, how long will it take to earn enough money to go on the trip? use the compound interest formula a = p (1 + i)n, where a is the accumulated amount, p is the principal, i is the interest rate per year, and n is the number of years.