Question

writing an equation to determine the number of hours worked
to babysit one child, fernando charges $10 to drive to the appointment plus $4 per hour. he saves 30% of the total amount he earns. brenna charges $6 per hour and saves 25% of the total amount she earns. which equation can be used to determine the number of hours, h, after which fernando and brenna will have saved the same amount of money?
10 + 0.3(4h) = 0.25(6h)
0.3(10) + 4h = 0.25(6h)
0.3(10 + 4h) = 0.25(6h)
0.3(14h) = 0.25(6h)

Explanation:

Step1: Calculate Fernando's savings

Fernando's total earnings: \(10 + 4h\) (fixed \(\$10\) plus \(\$4\) per hour). He saves \(30\%\) of it, so savings \(=0.3(10 + 4h)\)

Step2: Calculate Brenna's savings

Brenna's total earnings: \(6h\) ( \(\$6\) per hour). She saves \(25\%\) of it, so savings \(=0.25(6h)\)

Step3: Set equations equal

Since their savings are equal: \(0.3(10 + 4h)=0.25(6h)\)

Answer:

\(0.3(10 + 4h)=0.25(6h)\) (the third option)