Ultimate BOD of a river water sample is $20 \mathrm{mg} /$ L. BOD rate constant (natural log) is 0.15 day $^{-1}$. The respective values of $\mathrm{BOD}$ (in $\%)$ exerted and remaining after 7 days are:

(A) 45 and 55

(B) 55 and 45

(C) 65 and 35

(D) 75 and 25

Ultimate BOD of a river water sample is $20 \mathrm{mg} /$ L. BOD rate constant (natural log) is 0.15 day $^{-1}$. The respective values of $\mathrm{BOD}$ (in $\%)$ exerted and remaining after 7 days are:

(A) 45 and 55

(B) 55 and 45

(C) 65 and 35

(D) 75 and 25

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