A student is trying to determine the half-life of radioactive iodine-131. He measures the amount, A, of iodine-131in a sample every 8hours. His data are shown in the table.

Time(h)

0

8

16

24

32

40

48

Amount (G)

7.74

7.56

7.31

7.06

6.86

6.73

6.55

(a)Find an appropriate exponential model of the data points.

Amount at t, A(t)=____________

(b)Find the half-life of iodine-131 according to the exponential model in part

Half-life, t=___________.

Thank you!