Question

Probabilty of a 10-year flood to occur at least once in the next 5 years is

• A. 35%
• B. 40%
• C. 50%
• D. 65%

Answer 1

The correct option is B 40%

Probabiity corresponding to a 10 year return period is
$P=\frac{1}{10}=0.1$
The probability of flood occurring at least once in 5 year is
$=1-(1-P{)}^5=1-(1-0.1{)}^5$
$=1-0.5904$
$=0.4005=40.95\%$