Sally has seventy dollars to spend on eight books. After buying them she had thirteen dollars. How much did each book cost?
2 answers:
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Answer:
Step-by-step explanation:
we know that
Heron's Formula is a method for calculating the area of a triangle when you know the lengths of all three sides.
so
where
a, b and c are the length sides of triangle
s is the semi-perimeter of triangle
we have
<em>Find the semi-perimeter s </em>
s=
Find the area of triangle
simplify
Answer: $9 per hour at his job as a cashier and $8 per hour at his job delivering newspapers.
Step-by-step explanation:
1. Let's call the amount he got paid per hour at his job as a cashier: .
Let's call the amount he got paid per hour at his job delivering newspapers: .
2. Keeping on mind the information given in the problem above, you can make the following system of equations:
3. You can solve it by applying the Substitution method, as following:
- Solve for one of the variables from one of the equations and substitute it into the other equation to solve for the other variable and calculate its value.
- Substitute the value obtained into one of the original equations to solve for the other variable and calculate its value.
4. Therefore, you have:
Then:
Finally:
Therefore he got paid $9 per hour at his job as a cashier and $8 per hour at his job delivering newspapers.