+115 The exponential function
P = 500 × 0.88m
gives the amount in parts per million of PCBs in a contaminated site m months after a cleanup process begins.
(a) What is the weekly decay factor? Assume there are four weeks in each month. (Round your answer to two decimal places.)
(b)Find a formula that gives the amount P in parts per million w weeks after cleanup begins.
P = 500 × 0.97w
P = 500 × 0.94w
P = 500 × 3.52w
P = 500 × 0.60w
P = 500 × 0.22w
(c)What is the yearly decay factor? (Round your answer to two decimal places.)
(d)Find a formula that gives the amount P in parts per million y years after cleanup begins.
P = 500 × 0.99y
P = 500 × 0.07y
P = 500 × 10.56y
P = 500 × 0.22y
P = 500 × 5.28y
