A baker has a bag of flour that is 11% whole wheat and a bag of flour that is 63% whole wheat. How many cups of each type does the baker need to make 12 cups of a flour mixture that is 50% whole wheat?

a. 3 cups of the 11% flour and 9 cups of the 63% flour***
b. 9 cups of the 11% flour and 3 cups of the 63% flour
c. 3 cups of the 11% flour and 3 cups of the 63% flour
d. 9 cups of the 11% flour and 9 cups of the 63% flour

correct

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To solve this problem, we can use a basic equation:

(0.11x) + (0.63y) = 0.50(12)

Where:
- x represents the number of cups of the 11% flour
- y represents the number of cups of the 63% flour

By solving this equation, we can find the values of x and y. Let's calculate:

0.11x + 0.63y = 6

To make the equation simpler, we can multiply both sides of the equation by 100:

11x + 63y = 600

To continue, we need to use a system of equations. We'll create another equation to represent the total number of cups:

x + y = 12

Now we have a system of equations:

11x + 63y = 600
x + y = 12

To solve this system, we can use the substitution method. Let's solve for x in the second equation:

x = 12 - y

Now substitute this value into the first equation:

11(12 - y) + 63y = 600
132 - 11y + 63y = 600
52y = 468
y = 9

Now we can substitute the value of y back into x = 12 - y:

x = 12 - 9
x = 3

Therefore, the baker needs 3 cups of the 11% flour and 9 cups of the 63% flour to make a 50% whole wheat flour mixture. So, the correct answer is:

a. 3 cups of the 11% flour and 9 cups of the 63% flour

To solve this problem, we can use the concept of the weighted average. Let's break down the problem step by step:

1. Let's assume that the baker needs x cups of the 11% whole wheat flour and y cups of the 63% whole wheat flour to make a mixture of 12 cups that is 50% whole wheat.

2. We can write two equations to represent the given information:

Equation 1: (x cups of 11% flour) + (y cups of 63% flour) = 12 cups (total mixture)

Equation 2: [(11% whole wheat content * x cups of 11% flour) + (63% whole wheat content * y cups of 63% flour)] / (x cups + y cups) = 50% whole wheat content

3. Simplify Equation 2:

(0.11x + 0.63y) / (x + y) = 0.50

4. Cross-multiply to eliminate the fraction:

0.11x + 0.63y = 0.50(x + y)

0.11x + 0.63y = 0.50x + 0.50y

5. Rearrange the equation:

0.13x = 0.13y

x = y

6. From Equation 1, we know that x + y = 12. Since x and y are equal, we can rewrite the equation as:

2x = 12

x = 6

y = 6

7. Therefore, the baker needs 6 cups of the 11% flour and 6 cups of the 63% flour.

Thus, the correct answer is option c: 3 cups of the 11% flour and 3 cups of the 63% flour.