the level of a chemical pollution in a lake is 4.50 ppb and if the level increases by 0.20 ppb in the following month and by 5.0% less each month thereafter, what will be the maximum level
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the level of a chemical pollution in a lake is 4.50 ppb and if the level increases by 0.20 ppb in the following month and by 5.0% less each month thereafter, what will be the maximum level
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Verified answer
Month1 : pollution increases by 0.20 ppb parts per billion (10^-9)month 2 : increases by 0.20 * 0.95 as 0.95= (100-5)/100
month 3 : 0.20 * 0.95 * 0.95
So it is a geometric series : A = 0.20 R = 0.95
Sum to infinite terms is = A / (1 - 0.95) series converges as R < 1
So increase in pollution level = 0.20 / 0.05 = 4 ppb
Maximum pollution level : 4.5 ppb + 4 ppb = 8.5 ppb