Answer:
First brand of antifreeze: 21 gallons
Second brand of antifreeze: 9 gallons
Step-by-step explanation:
Let's call A the amount of first brand of antifreeze. 20% pure antifreeze
Let's call B the amount of second brand of antifreeze. 70% pure antifreeze
The resulting mixture should have 35% pure antifreeze, and 30 gallons.
Then we know that the total amount of mixture will be:

Then the total amount of pure antifreeze in the mixture will be:


Then we have two equations and two unknowns so we solve the system of equations. Multiply the first equation by -0.7 and add it to the second equation:



+

--------------------------------------



We substitute the value of A into one of the two equations and solve for B.


There are 100 pence in a Pound. So we have to divide 25 pence over this pound, or over 100 pence: 25/100 is 1/4, so 25 Pence is one forth of a Pound (or 25 % in percentages):
Answer: $375
Step-by-step explanation:
Given : The probability of winning $100 : P(100)= 0.25
The probability of winning $200 : P(200)= 0.50
The probability of winning $1000 : P(1000)= 0.25
Now, the the expected value of that lottery ticket is given by :-

Hence, the the expected value of that lottery ticket =$375
Answer:
x = 8
Step-by-step explanation:
An undefined slope indicates that the line is vertical and parallel to the y- axis with equation
x = c ( c is the value of the x- coordinates the line passes through )
the line passes through (8, 4 ) with x- coordinate 8 , then
x = 8 ← equation of line