Question

question
type of cookie cost per cookie, in dollars
chocolate chip $0.73
double chocolate $0.82
oatmeal raisin $0.70
sugar x
butter pecan $0.86
the table above shows a bakerys cost per cookie for each of the five types of cookies the bakery sells. if the mean cost per cookie is $0.73, what is the cost per cookie, in dollars, for a sugar cookie?
$0.54
$0.67
$0.79
$0.84

Explanation:

Step1: Recall mean formula

The mean $\bar{x}=\frac{\sum_{i = 1}^{n}x_{i}}{n}$. Here, $n = 5$, and $\bar{x}=0.73$. The values are $0.73,0.82,0.70,x,0.86$. So, $0.73=\frac{0.73 + 0.82+0.70+x + 0.86}{5}$.

Step2: Cross - multiply

Multiply both sides of the equation by 5: $0.73\times5=0.73 + 0.82+0.70+x + 0.86$.
$3.65=3.11 + x$.

Step3: Solve for $x$

Subtract 3.11 from both sides: $x=3.65 - 3.11$.
$x = 0.54$.

Answer:

$0.54$