There was a sample of 350 milligrams of a radioactive substance to start a study. since then, the sample has decayed by 5.7% each year. let t be the number of years since the start of the study. let y be the mass of the sample in milligrams. write an exponential function showing the relationship between y and t.

y = 350(0.943)t

Step-by-step explanation:

Mass of sample after t years is given by

y = Initial mass * (1 - r)t

In this case,

Initial mass = 350 mg

r = 5.7% = 0.057

Therefore,

y = 350(1 - 0.057)t

=> y = 350(0.943)t

Therefore, relationship between y and t is given by

y = 350(0.943)t

341

step-by-step explanation:

all you have to do is 9x31 (which equals 279) and then 20x31 (which equals 620). then you have to subtract. 620-279=341.