A painting sold for $277 in 1978 and was sold again in 1990 for $485. Assume that the growth in the value V of the collector's item was exponential. a) Find the value k of the exponential growth rate. Assume V = 277. k = (Round to the nearest thousandth.) b) Find the exponential growth function in terms of t, where t is the number of years since 1978. V(t)= c) Estimate the value of the painting in 2015. $ (Round to the nearest dollar.) d) What is the doubling time for the value of the painting to the nearest tenth of a year? years (Round to the nearest tenth.) e) Find the amount of time after which the value of the painting will be $2173. years (Round to the nearest tenth.)