The proportion
peanuts : raisins : chocolate chips = 4 : 6 : 2
tells you that peanuts make up
4/(4+6+2) = 1/3
of the total quantity of the mix.
The quantity of peanuts required is (1/3)*(48 ounces) = 16 ounces (or 1 pound).
_____
In the 48 ounces of mix, 1 part = 4 ounces.
A) Think of the amount as a fraction or ratio: 160/5 now, we want the denominator to be equivalent to 1 hour so we divide 5 by 5 to get 1. What we do to the bottom, we do to the top, so we do 160 divided by 5 = 32 bagels in 1 hour.
B) Now take 160/5 and set the denominator equal to 12. 5 times 2.4 equals 12, so then multiply 160 times 2.4 = 384 bagels in 12 hours. Hope this helps!