To solve the problem, let's break it down step by step.
### a) Write an equation for total monthly expenses \( E \) in terms of the number of donuts \( d \).
The total monthly expenses \( E \) can be calculated as the sum of the variable costs (cost per donut multiplied by the number of donuts) and the fixed costs (utilities and salaries).
- Cost per donut: \( \$0.10 \)
- Fixed costs (utilities + salaries): \( \$1100 + \$5100 = \$6200 \)
The equation for total expenses \( E \) is:
\[
E = 0.10d + 6200
\]
### b) Determine how many donuts were produced in March if the total expenses were \( \$14150 \).
We can set the total expenses equal to the calculated expenses equation:
\[
14150 = 0.10d + 6200
\]
Now, we can solve for \( d \):
1. Subtract \( 6200 \) from both sides:
\[
14150 - 6200 = 0.10d
\]
\[
7930 = 0.10d
\]
2. Divide both sides by \( 0.10 \):
\[
d = \frac{7930}{0.10} = 79300
\]
So, the number of donuts produced in March is \( 79300 \).
### c) Calculate the shop's revenue in March.
The shop sells each donut for \( \$0.50 \). Therefore, the revenue \( R \) can be calculated as:
\[
R = \text{price per donut} \times \text{number of donuts}
\]
\[
R = 0.50 \times 79300
\]
\[
R = 39650
\]
So, the revenue in March is \( \$39650 \).
### d) Calculate the profit made by the store in March.
Profit can be calculated as the difference between revenue and expenses:
\[
\text{Profit} = R - E
\]
\[
\text{Profit} = 39650 - 14150
\]
\[
\text{Profit} = 25500
\]
So, the profit made by the store in March is \( \$25500 \).
### Summary of Answers:
- a) Equation: \( E = 0.10d + 6200 \)
- b) Donuts produced: \( 79300 \)
- c) Revenue in March: \( \$39650 \)
- d) Profit: \( \$25500 \)
a) \( E = 0.10d + 6200 \)
b) Donuts produced: \( 79300 \)
c) Revenue in March: \( \$39650 \)
d) Profit: \( \$25500 \)