Trey mechanic will fix Trey's car at a rate of $20 per hour, plus $400 for the cost of a part. Trey's neighbor already has the needed part and will fix the car for only $70 per hour. For how many hours will the cost of having the car fixed by either person be the same?

8 hours.

Step-by-step explanation:

let x represent number of hours.

We have been given that Trey mechanic will fix Trey's car at a rate of $20 per hour, plus $400 for the cost of a part.

So total cost of repairing a car for x hours by Trey mechanic would be .

We are also told that the neighbor has the needed part and will fix the car for only $70 per hour. So total cost of repairing a car for x hours by neighbor would be .

To find the number of hours, when the cost of fixing the car by either person will be equal, we need to equate both expressions as:

Let us solve for x.

Therefore, after 8 hours the cost of having the car fixed by either person will be the same.

total amount of money that he should pay if he has not used his duty free exemption is $98

step-by-step explanation:

given a united states citizen returning to the states declares the following items at the customs office: 3 shirts at $8.50 each 2 dresses at $27.50 each 1 pair of gold cuff links at $17.50 per pair. we have to find how much he pay

cost of 3 shirts if one cost at $8.50 is

cost of 2 dresses if one cost at $27.50 is  

cost of 1 pair of gold cuff at $17.50

so, total amount of money that he should pay if he has not used his duty free exemption is   $25.5+$55+$17.50=$98

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204