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This problem trains for: Math Kangaroo 5-6, Math Kangaroo 7-8, SAT-I, AMC-8, GMAT.

If white flour is 59% of a white bread mix and proteins form 12% of the flour, approximately what percentage of white bread is protein?

Let us denote the amount of bread with B, the amount of flour with F and the amount of protein with P. Then, we have:

equation

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Substitute the first relation for the value of F in the second one:

equation

The unknown percentage x is:

equation

Solve for x:

equation

equation

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