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:
34
Step-by-step explanation:
Substitute 2 for t in your formula
Answer:
48
Step-by-step explanation:
!3x5 is 48
The 99.87th percentile, or the area to the left of the 3 standard deviation mark it 99.87% better than everyone/everything else.