The answer is 56%
You first divide 28 by 50=.56, then since it's a decimal, you move the decimal twice to the right to make a percentage=56%
Y=x-4
x=y+4
y=-3(y+4)
y=-3y-12
4y=-12
y=-3
x=1
The difference in gallons per day used is 3.6.
The formula to calculate a z-score is:

,
where X is the value used to calculate the score, μ is the mean and σ is the standard deviation. We have the z-scores so we must work backward:

For both equations, we will cancel the 1.2 by multiplying both sides:

Now we will cancel 2.2 from both equations by adding it to both sides:
3.6+2.2=X-2.2+2.2 and 0+2.2=X-2.2+2.2
5.8=X and 2.2=X
The difference in gas used per day would be given by
5.8-2.2 = 3.6.
After two hours the prices will meet a 760
$550+105=655 |655+105= 760
660+50= 710 |710+50= 760
They meet in the second hour so in the second hour they will charge the same.