GATE Exam Questions - Engineering

Q1:

The 5-day BOD of a wastewater sample is obtained as 190 mg/l (with k = 0.01 h-1). The ultimate oxygen demand (mg/l) of the sample will be

A 3800

B 475

C 271

D 190

ANS:C - 271

Why e? Can't we use base 10?

Lt=Lo (1-10^kt).