Answer:
Step-by-step explanation:
9y-4 = 50
9y = 54
y= 6
9y-4+7x+xy = 180
9(6)-4+7x+6x= 180
54-4+13x = 180
13x+50 = 180
13x = 130
x = 10
Answer:
a) 22.94 psi
b) 
Step-by-step explanation:
a)The pressure at which will trigger a warning is
31 - 31*0.26 = 22.94 psi
b) The probability that that the TPMS will trigger warning at 22.94 psi, given that tire pressure has a normal distribution with average of 31 psi and standard deviation of 2 psi

where x = 22.94, 


The last option all the way to the right
Answer:
10 gallons of the 1st brand and 30 gallons of the second brand.
Step-by-step explanation:
The equation I came up with is 0.6x+0.8y=0.75(x+y), with x and y representing the total amount of mixture of each brand. Meaning, 0.6x is the amount of pure antifreeze in the first brand, 0.8y is pure antifreeze in the second brand, and 0.75(x+y) is the amount of pure antifreeze there's supposed to be when you mix the two brands together.
Now, the question also says that the mixture is 40 gallons. The total mixture of the 2 brands is basically x+y = 40, then you can minus x from both sides and get y = 40-x, then you substitute it into the original equation: 0.6x+0.8(40-x)=0.75(x+40-x), x = 10, the amount of mixture from the first brand, which also means that 30 gallons is the amount of mixture from the second brand.