Question

The record of a weather station shows that out of the past 200 consecutive days, its weather forecasts were correct 150 times.
What is the probability that the weather report will be incorrect for the next day?

• A. 0.75
• B. 0.25
• C. 0.35
• D. 0.2

Answer 1

The correct option is B 0.25

We know, for an event E,
$P\left(E\right)=\frac{\text{Number of trials in which the event happened}}{\text{Total number of trials}}$

The weather station's forecast was correct on 150 days out of 200 days.
$⟹$ The forecast was not correct on 50 of the days.
Therefore, the probability that the report will be incorrect is:
$P\left(E\right)=\frac{\text{Number of days in which the forecast was not correct}}{\text{Total number of days}}=\frac{50}{200}=\frac{5}{20}=0.25$