Algebra 1 : How to find direct variation

Study concepts, example questions & explanations for Algebra 1

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Example Questions

Example Question #211 : Functions And Lines

The amount of money Billy earns is directly proportional to his hours worked.  Suppose he earns  every eight hours of work.  What is the minimum hours Billy must work in order to exceed ?  Round to the nearest integer.

Possible Answers:

Correct answer:

Explanation:

Write the formula for direct proportionality.

Let:

Substitute twelve dollars and eight hours into this equation to solve for .

Divide by eight on both sides.

Substitute  back into the formula.

To find out the minimum number of hours Billy must work to make , substitute  into  and solve for .

Multiply by two thirds on both sides.

Simplify both sides.

Billy must work at least  hours to earn as much required.

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