can someone help me with these problems

You just won the $45 million lottery. You will receive $2.5 million a year for the next 15 years plus an additional payment of $7.5 million at the end of 15 years. The interest rate is 11 percent. How much is your lottery prize worth today? (Enter your answer as a positive number rounded to 2 decimal places.) At an interest rate of 13 percent annually, how long will it take for a $1,000 to double? To triple? (Round your answers to 2 decimal places.) years Time needed to double Time needed to triple years