Maths
posted by Sue on .
Please help!!!
The mass of a particular substance is known to grow exponentially at a rate of 1.5% per day. Its initial mass was 230 grams and, after t days, it weighed 325 grams.
The equation modelling this growth is
230×1.015 t = 325.
Use the method of taking logs to solve this equation for t, giving your answer correct to the nearest day.

I think you have a typo, and meant to say ...
230(1.015)^t = 325
(your equation would have a linear growth, not exponentially)
1.015^t = 325/230 = 1.4130435
log(1.015^t) = log 1.4130435
t = log 1.4130435/log 1.015 = 23.222
so it will take appr. 23 days.