Need help with practice question

A particular country's exports of goods are increasing exponentially. The value of the exports, t years after 2007, can be approximated by V(t) = 1.3 0.039 where t= 0 corresponds to 2007 and V is in billions of dollars. a) Estimate the value of the country's exports in 2007 and 2011. b) What is the doubling time for the value of the country's exports? a) The value of the country's exports in 2007 is $ billion. (Simplify your answer. Round to the nearest tenth as needed. Do not include the $ symbol in your answer.) The value of the country's exports in 2011 is $ billion. (Simplify your answer. Round to the nearest tenth as needed. Do not include the $ symbol in your answer.) b) The doubling time is approximately years. (Simplify your answer. Round to the nearest integer as needed.)