Ireally need !

the number of hours, t, that bacteria spread 10-fold can be modeled by the equation b(t) = b0(10)^3t. there are five bacteria present initially and a biologist wishes to find out how many hours will elapse until there are 2,000 bacteria present. what is the exact value for the number of hours elapsed, t, in the equation 2,000 = 5(10)^3t?

t equals start fraction log of forty over three end fraction
t equals start fraction log of two thousand over three times log of fifty end fraction
t equals start fraction log of four hundred over log of three end fraction
t equals start fraction log of four hundred over three end fraction