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 answer is B because it is the only one where the line intersects on the y - axis at -1/2 and 2/3, which are the y -intercepts
The answer is three significant figures. The 1 and the 7 are both significant, because they are non-zero quantities.
This is where significant figures gets a little more complicated, because if a zero is used as a placeholder (i.e. 0.00027 cm) then it is insignificant.
But in the case above, the zero isn't being used as a placeholder, and thus, is significant.
Answer: 3 games
Step-by-step explanation:
10.5
First subtract 3 because you will need shoes.
7.50
Now divide by 2.50
7.5/2.5
3 GAMES