Question

How long will it take for an investment of $2000 to double in value if the interest rate is 8.5% per year, compounded continuously? (Round your answer to two decimal places.)
yr

(b)

A 15-g sample of radioactive iodine decays in such a way that the mass remaining after t days is given by

m(t) = 15e^−0.077t,

where

m(t)

is measured in grams. After how many days is there only 1 g remaining? (Round your answer to the nearest whole number.)
days

Answer 1

0 Given given Brincipe = $2000 Rate at intenst s= 8.5% = 0.085. amount ich double to minciple so Amount A - $4000. for ompounded Ontineously A = pert 0.085t 4000 = 2000 Formula 9 = 0.085t apply lin' on both sides en (2) - 0.085€ ene. t = ln (2) 0.085 ( It = 8.15 years. line =) mass m(t) = 15e 0.0 Here to no. of days given mass mt - 19. = I= ise 0.077€ 1/18 = -0.077€ en (ts) = o.ottine t = ln (1115) - 0.077 t = 35 days.