The mass of a particular substance is known to grow exponentially at a rate of 7.1% per day. Its initial mass was 45 grams and, after 1' days, it weighed 122 grams The equation modelling this growth is 45 x 1.071t 122. Use the method of taking logs to solve this equation for 1*, giving your answer correct to the nearest day. (Your answer should be a number, without units)