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.
Yes. There are 2 decimal places in .51 and 3 in 2.427.
So there would be a total of 5 decimal places.
Answer:
The answer is $16.45
Step-by-step explanation:First, you have to multiply $0.95 x 9 = $8.55
Then, you have to subtract $25.00-$8.55 = $16.45
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Answer: D
Step-by-step explanation: