Question

Dustin is mixing concrete. A formula for concrete calls for 3/8 gal of water. Dustin wants to make 7/9 more concrete than the formula creates. How much water should Dustin use? Express your answer as a fraction in simplest form

Answer 1

So, if he wants to make $\frac{7}{9}$ more concrete, he should use $\frac{7}{9}$ more water!

so he should use 1 of the planed water plus $\frac{7}{9}$ of the planned water, that is $\frac{9+7}{9}$ or $\frac{16}{9}$ of what the formula says.

so we multiply this by what the formula says:

$\frac{16}{9}*\frac{3}{8}=\frac{2}{9}*\frac{3}{1}=\frac{2}{3}*\frac{1}{1}$

so he has to use 2/3 gal of water