
a.
The system of equations of the fuel mixture.
a.

Answer to Problem 50E
{x+y=500.87x+.92y=445
Explanation of Solution
Given information:
Five hundred gallons of 89 -octane gasoline is obtained by mixing 87 -octane gasoline with 92 -octane gasoline.
(a) Write a system of equations in which one equation represents the amount of final mixture required and the other represents the amount of 87 -and 92 -octane gasolines in the final mixture.
Calculation:
Let x represent the number of gallons of 87 -octane
Let y represent the number of gallons of 92 -octane
Sum of two types of gasoline equalling 500 gallons.
According to the given information, the equations are as shown below:
x+y=500.87x+.92y=(.89)(500)
Simplify by the following the order of operations:
x+y=500.87x+.92y=445
Therefore, the system of equations are {x+y=500.87x+.92y=445 .
b.
The solution of the system of equations by graphically.
b.

Answer to Problem 50E
(300,200) .
Explanation of Solution
Given information:
Five hundred gallons of 89 -octane gasoline is obtained by mixing 87 -octane gasoline with 92 -octane gasoline.
(b) Use a graphing utility to graph the two equations in part(a) in the same viewing window. As the amount of 87 -octane gasoline increases, how does the amount of 92 -octane gasoline change?
Calculation:
The two equations in part (a) are:
{x+y=500.87x+.92y=445
Byusing a graphing utility the two equations are as shown below:
The amount of 92 -octane gasoline change, because the 87 -octane gasoline increases than y decreases.
Thus, the solution is (300,200) .
c.
To explain:The type of gasoline required to obtain the gallons.
c.

Answer to Problem 50E
300 Gallons of 87 -octane gasoline and 200 gallons of 92 -octane gasoline
Explanation of Solution
Given information:
Five hundred gallons of 89 -octane gasoline is obtained by mixing 87 -octane gasoline with 92 -octane gasoline.
(c) How much of each type of gasoline is required to obtain the 500 gallons of 89− octane gasoline?
Calculation:
Let x represent the number of gallons of 87 -octane
Let y represent the number of gallons of 92 -octane
Sum of two types of gasoline equalling 500 gallons.
According to the given information, the equations are as shown below:
x+y=500.87x+.92y=(.89)(500)
Simplify by the following the order of operations:
x+y=500.87x+.92y=445
Multiply the first equation by −9.2 so that the y variables in the system of equations are opposites.
−.92(x+y=500)−.92x−.92y=−460
Add the equations together to eliminate the y variables:
−.92x−.92y=−460 (1).87x+.92y=445 (2)
Divide both sides by −0.5 to solve for x :
−0.5x=−15x=300
Plug x=300 into the first equation of the system to get the value of y :
300+y=500y=200
Thus, 300 gallons of 87 -octane gasoline and 200 gallons of 92 -octane gasoline are required to obtain 500 gallons of 89 -octane gasoline.
Chapter 7 Solutions
EBK PRECALCULUS W/LIMITS
- Which of the following is the general solution to y′′ + 4y = e^2t + 12 sin(2t) ?A. y(t) = c1 cos(2t) + c2 sin(2t) + 1/8 e^2t − 3t cos(2t)B. y(t) = c1e^2t + c2e^−2t + 1/4 te^2t − 3t cos(2t)C. y(t) = c1 + c2e^−4t + 1/12 te^2t − 3t cos(2t)D. y(t) = c1 cos(2t) + c2 sin(2t) + 1/8 e^2t + 3 sin(2t)E. None of the above. Please include all steps! Thank you!arrow_forwardShow that i cote +1 = cosec 20 tan 20+1 = sec² O २ cos² + sin 20 = 1 using pythagon's theoremarrow_forwardFind the general solution to the differential equationarrow_forward
- charity savings Budget for May travel food Peter earned $700 during May. The graph shows how the money was used. What fraction was clothes? O Search Submit clothes leisurearrow_forwardExercise 11.3 A slope field is given for the equation y' = 4y+4. (a) Sketch the particular solution that corresponds to y(0) = −2 (b) Find the constant solution (c) For what initial conditions y(0) is the solution increasing? (d) For what initial conditions y(0) is the solution decreasing? (e) Verify these results using only the differential equation y' = 4y+4.arrow_forwardAphids are discovered in a pear orchard. The Department of Agriculture has determined that the population of aphids t hours after the orchard has been sprayed is approximated by N(t)=1800−3tln(0.17t)+t where 0<t≤1000. Step 1 of 2: Find N(63). Round to the nearest whole number.arrow_forward
- 3. [-/3 Points] DETAILS MY NOTES SCALCET8 7.4.032. ASK YOUR TEACHER PRACTICE ANOTHER Evaluate the integral. X + 4x + 13 Need Help? Read It SUBMIT ANSWER dxarrow_forwardEvaluate the limit, and show your answer to 4 decimals if necessary. Iz² - y²z lim (x,y,z)>(9,6,4) xyz 1 -arrow_forwardlim (x,y) (1,1) 16x18 - 16y18 429-4y⁹arrow_forward
- Evaluate the limit along the stated paths, or type "DNE" if the limit Does Not Exist: lim xy+y³ (x,y)(0,0) x²+ y² Along the path = = 0: Along the path y = = 0: Along the path y = 2x:arrow_forwardshow workarrow_forwardA graph of the function f is given below: Study the graph of ƒ at the value given below. Select each of the following that applies for the value a = 1 Of is defined at a. If is not defined at x = a. Of is continuous at x = a. If is discontinuous at x = a. Of is smooth at x = a. Of is not smooth at = a. If has a horizontal tangent line at = a. f has a vertical tangent line at x = a. Of has a oblique/slanted tangent line at x = a. If has no tangent line at x = a. f(a + h) - f(a) lim is finite. h→0 h f(a + h) - f(a) lim h->0+ and lim h h->0- f(a + h) - f(a) h are infinite. lim does not exist. h→0 f(a+h) - f(a) h f'(a) is defined. f'(a) is undefined. If is differentiable at x = a. If is not differentiable at x = a.arrow_forward
- Calculus: Early TranscendentalsCalculusISBN:9781285741550Author:James StewartPublisher:Cengage LearningThomas' Calculus (14th Edition)CalculusISBN:9780134438986Author:Joel R. Hass, Christopher E. Heil, Maurice D. WeirPublisher:PEARSONCalculus: Early Transcendentals (3rd Edition)CalculusISBN:9780134763644Author:William L. Briggs, Lyle Cochran, Bernard Gillett, Eric SchulzPublisher:PEARSON
- Calculus: Early TranscendentalsCalculusISBN:9781319050740Author:Jon Rogawski, Colin Adams, Robert FranzosaPublisher:W. H. FreemanCalculus: Early Transcendental FunctionsCalculusISBN:9781337552516Author:Ron Larson, Bruce H. EdwardsPublisher:Cengage Learning





