please answer to the question in the attachment file and correct my mistake.

The half-life of bismuth-210, 2103i, is 5 days. {a} If a sample has a mass of 334 mgIr find the amount remaining after 15 days. '43 J mg (b) Find the amount remaining after t days. _{_c)_ Esijmate the amount remaining after 3 weeks. (Round your answer to one decimal place.) 320-3 1)! mg (cl) Use a graph to estimate the time required for the mass to be reduced to 1 mg. (Round your answer to one decimal place.) 348.2 :x days iiiI