Last question i need ! < 3

a radioactive substance decays at a rate of 2% per day. if there are 50 grams of the
substance left after 34 days, how much was there at the beginning of the 34 days?
round to two decimal places.

Without multiplying, tell which product is larger and why. 5 × 1/3 or 5 × 2/3 a)5 × 1/3 because 1/3 is less than 2/3 b) 5 × 1/3 because 1/3 is greater than 2/3 c) 5 × 2/3 because 1/3 is less than 23 d) 5 × 23 because 1/3 is greater than 2/3