Question

The record of weather stations report shows that out of the past $100$ consecutive days, its weather forecast was correct $35$ times. Find the probability that on a given day it was not correct.

• A. $\frac{13}{20}$
  
• B. $\frac{7}{20}$
  
• C. $\frac{11}{20}$
  
• D. $\frac{1}{20}$
  

Answer 1

The correct option is A $\frac{13}{20}$


Total number of days $=100$
Number of days weather forecast was correct $=35$
Number of days weather forecast was not correct
$=100-35$
$=65$

The probability $\text{P(E)}$ that the weather forecast was not correct is:

$\text{P(E)}=\frac{\text{Number of days weather forecast was not correct}}{\text{Total number of days}}$

$\text{P(E)}=\frac{65}{100}$

$\text{P(E)}=\frac{13}{20}$

The probability that the weather forecast was not correct is $\frac{13}{20}$.

Therefore, option (a.) is the correct answer.