Question 458739
6) Which of the four systems can be used to solve the following problem: A coffee shop carries two blends of coffee. 
The first blend contains 20% Mexican coffee and 80% Columbian coffee. 
The second blend contains 60% Mexican coffee and 40% Columbian coffee. 
How many pounds of each blend should be combined to create a new blend that contains 30 pounds of Mexican coffee and 70 pounds of Columbian coffee? 
Let x be the amount of blend 1 and y the amount of blend 2. 
(A)
Columbian Coffee:::0.8x+.4y=70
Mexican Coffee:::::.2x+.6y=30 
I chose (A)
GOOD
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7) Which of the three systems can be used to solve the following problem: Last year an investment firm invested 200 million dollars in three mutual funds.
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Mutual fund #1 yielded a 4% return, mutual fund #2 5%, and mutual fund #3 8%. The total amount of return from the three funds was 13 million dollars. 
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It was known that the amount invested in mutual fund #1 and mutual fund #2
combined equaled the amount invested in mutual fund #3. Let x be the amount invested in mutual fund #1, y mutual fund #2, and z mutual fund #3. 
(A)
Interest Eq::::4x+5y+8z= 1300
Quantity Eq:::: x+y-z= 0
Quantity Eq:::::x+y+z= 200 
I chose (A)
GOOD
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8) The initial array corresponding to a system is 
(1 0 5 | -2)
(-1 1 -3 | 5)

. Which of the following is
the GENERAL solution to the system?
(B)
x=-2-5z
y=3-2z
z=any real number 
I chose (B)
are these correct?
GOOD
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Cheers,
Stan H.