+218 Here's the question:
Brad mixes seeds to attract birds. His Blue mix is 55% sunflower and 45% bluegrass. His Rye mix
is 30% sunflower and 70% ryegrass. His Master mix combines some of each of the Blue and Rye mixes.
If Master mix is 45% sunflower, how much of each kg of Master mix is Blue mix?
A) 350g B) 400g C) 600g D) 650g
+591 We can say $b\%$ of the master mix is Blue mix, and $r\%$ of the mastermix is Rye mix, so we have
$b+r=100$
$\frac{11b}{20}+\frac{3r}{10}=45$
we can multiply both sides of the second equation by 20 so that we are dealing with whole numbers instead of fractions, so we have:
$11b+6r=900$
We can multiply both sides of the first equation by 6, so that we can eliminate the r:
$6b+6r=600$
$11b+6r-6b-6r=900-600=5b=300$
$b\%=60\%$
so, out of each kg of mastermix or every 1000 grams of mastermix, there are $1000\cdot\frac{60}{100}=\boxed{600g}$ or $\boxed{C}$
