Question

A college student realized that he was spending too much money on fast food. For the remaining 5 months of the year his goal is to spend a mean of $50 a month towards fast food. How much can he spend in December, taking into consideration that in the other 4 months he spent $80 $40, $30, and $50, respectively? Round your answer to two decimal places, if necessary

Answer 1

$50 in December.

1) Given that this college student wants to control his budget to fall within an expenditure of $50 per month, and this is a mean, we can write out the following expression:

`\begin{gathered} (80+40+30+50+x)/(5)=50 \\ \\ 80+40+30+50+x=250 \\ \\ 150+50+x=250 \\ \\ 200+x=250 \\ \\ 200-200+x=250-200 \\ \\ x=50 \end{gathered}`

Note that we have used the Arithmetic Mean formula, considering that those four months and December: 5 months.

2) Thus he can only spend $50 in December in order to keep the mean