Please solve

A painting is purchased as an investment for $150. If its value increases continuously so that it doubles every 4 years, then its value is given by the function V(t) = 150 . 2t/4 for t > 0 where t is the number of years since the painting was purchased, and V(t) is its value (in dollars) at time t. Find V(12) and V(16). V(12) = $ V(16) = $