On Decemeber 18th, there is a 75% chance that Santa will come to the mall that day and a 55% chance that your best friend will be at the mall. There is a 40% chance that your best friend will be there AND Santa will come to that mall. What is the probability that Santa will come to the mall OR your best friend will be there?

The probability that Santa will come to the mall OR your best friend will be there is 47.4%

Step-by-step explanation:

1. Let's review the information provided to us to answer the question correctly:

Probability that Santa will come to the mall on December 18th = 75%

Probability that your best friend will be at the mall on December 18th = 55%

Probability that Santa will come to the mall on December 18th AND your best friend will be there = 75% * 55% = 41.3% not just 40%

2. What is the probability that Santa will come to the mall OR your best friend will be there?

For answering this question, we should calculate first the probability that Santa will not come to the mall on December 18th AND your best friend will not be there, this way:

Probability that Santa will not come to the mall on December 18th AND your best friend will not be there = 25% * 45% = 11.3%

Now, we know that the probability that Santa will come to the mall on December 18th AND your best friend will be there is 41.3% and the probability that Santa will not come to the mall on December 18th AND your best friend will not be there is 11.3%.

Therefore, the probability that Santa will come to the mall OR your best friend will be there is:

100% - 41.3% - 11.3% = 100% - 52.6% = 47.4%

The probability that Santa will come to the mall OR your best friend will be there is 47.4%