The order of operations is
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction
For this problem, we have M and D. We first do division. Not always multiplication is first.
So we divide 20 by 5, which gets you 4, and multiply by 2, which is 8.
8 IS YOUR FINAL ANSWER,
n and t are proportional so you know they will be on the opposite ends of the equal sign. Then you know that the items are purchased at the constant price of $3. That means you do the number of items times 3 to get the total cost.
