Question

1/3 cup of flour is used to make 5 dinner rolls. how many cups of flour are needed to make 3 dozen dinner rolls

Answer 1

F = Cup of flour

D = Dinner roll(s)

12 = A dozen

36 = Three dozen

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1/3 * F = 5 * D

n * F = 36 * D

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$\frac { 1 }{ 3 } F=5D\\ \\ 3\cdot \frac { 1 }{ 3 } F=3\cdot 5D\\ \\ F=15D$

$nF=36D\\ \\ n=\frac { 36D }{ F }$

This means that...

$n=\frac { 36D }{ 15D } \\ \\ n=\frac { 36 }{ 15 } \\ \\ n=\frac { 3\cdot 12 }{ 3\cdot 5 } \\ \\ n=\frac { 12 }{ 5 } \\ \\ n=\frac { 10 }{ 5 } +\frac { 2 }{ 5 } \\ \\ n=2+\frac { 2 }{ 5 }$

And this means that two cups of flour and 2/5 of a cup of flour are required to make 3 dozen dinner rolls.