The mean weight of five complete computer stations is 163 pounds. The weights of four of the computer stations are 155 pounds, 1
1 answer:
You might be interested in
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.