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.
The eight graders' goal is more than the teachers' goal.
The teachers' goal is less than the eight graders' goal.
Answer: F) 7 mph
<u>Step-by-step explanation:</u>
The line you drew is correct but you read the graph wrong.
The line drawn from 15 hours of training (bottom axis) meets the "line of best fit" at the average running speed (left axis) between 6 and 8, which is 7.
48 cups because there are 8 cups in a bottle and 8 times 6 is 48
Answer:
the correct option is E. d is biased.
Step-by-step explanation:
As given,
The expected value of d hat is not equal to D.
We know that,
The unbiased-ness is the property that tells the expected value of d is equal to D
So, the correct option is E. d is biased.