Answer:
20 gallons were used from the tank with the octane rating of 80.
Step-by-step explanation:
Given : One tank of gasoline has an octane rating of 140 and another tank of gasoline has an octane rating of 80. To obtain a mixture of 60 gallons with an octane rating of 120.
To find : How many gallons should be used from the tank with the octane rating of 80?
Solution : Let x be the volume of gas whose octane rating is 140 and
y be the volume of gas whose octane rating is 80.
Then, we form the equation as:
(1) 

or
.........[3]
(2) 
Now multiply equation (2) by 4
...........[4]
Subtract (4) from (3)



Put x in equation [4] we get,





Therefore, x=40 and y=20
So, 20 gallons were used from the tank with the octane rating of 80.
Answer:
12
Step-by-step explanation:
4y - 2x
= 4(7) - 2(8)
= 28 - 16
= 12
9514 1404 393
Answer:
x = 30
Step-by-step explanation:
Supplementary angles total 180°.
5x° +x° = 180°
6x = 180
x = 180/6 = 30
The value of x is 30.
the answer is -3/2 and -11/2
Answer:
Step-by-step explanation:
would be graph x