91Ó°ÊÓ

The number of food orders at drive-thru centres of four fast-food chains are provided.

Some orders are accurate, while others are inaccurate.

For three events, A, B, and C, to occur individually or simultaneously, the following probability is calculated:

$P\left(A\text{or}B\text{or}C\right)=P\left(A\right)+P\left(B\right)+P\left(C\right)-P\left(A\text{and}B\right)-P\left(A\text{and}C\right)-P\left(B\text{and}C\right)$

The subtotals for each chain are tabulated below:

The total number of food orders is equal to 1118.

Let E be the event of selecting a food order from Burger King.

Let F be the event of selecting a food order from Taco Bell.

Let G be the event of selecting an accurate food order.

The number of food orders from Burger King is equal to 318.

The probability of selecting a food order from Burger King,

$P\left(E\right)=\frac{318}{1118}$

The number of food orders from Taco Bell is equals 158.

The probability of selecting a food order from Taco Bell,

.$P\left(F\right)=\frac{158}{1118}$

The number of accurate food orders is equal to 987.

The probability of selecting an accurate food order,

$P\left(G\right)=\frac{987}{1118}$

The number of orders from Burger King and Taco Bell is equal to 0. Thus,

.$P\left(E\text{and}F\right)=\frac{0}{1118}$

The number of accurate orders from Burger King is equal to 264. Thus,

$P\left(E\text{and}G\right)=\frac{264}{1118}$

The number of accurate orders from Taco Bell is equal to 145. Thus,

$P\left(F\text{and}G\right)=\frac{145}{1118}$

.

The probability of getting an order from Burger King or Taco Bell or an accurate order is calculated as follows:

$$\begin{gathered} P\left(E\text{or}F\text{or}G\right)=P\left(E\right)+P\left(F\right)+P\left(G\right)-P\left(E\text{and}F\right)-P\left(E\text{and}G\right)-P\left(F\text{and}G\right) \\ =\frac{318}{1118}+\frac{158}{1118}+\frac{987}{1118}-\frac{0}{1118}-\frac{264}{1118}-\frac{145}{1118} \\ =\frac{1054}{1118} \\ =0.9428 \end{gathered}$$

Therefore, the probability ofgetting an order from Burger King or Taco Bell or an accurate orderis equal to0.943.