Question

The return period for the annual maximum flood of a given magnitude is 8 years. The probability that this flood magnitude will be exceeded once during the next 5 years is

• A. 0.625
• B. 0.366
• C. 0.487
• D. 0.529

Answer 1

The correct option is B 0.366

Given,
T = 8 years
$p=\frac{1}{T}=\frac{1}{8}=0.125$

$q=1-p$
$=1-0.125=0.875$

Probability of flood magnitude will be exceeded once during the next 5 years
$={}^n{C}_r{p}^r{q}^{n-r}$

$={}^5{C}_1\left(0.125{)}^1\right(0.875{)}^{5-1}$

$=0.366$