Question

A recipe calls for 5 ounces of vinegar and 10 ounces of oil. Daren is making dressing with 9 ounces of vinegar using the same ratio of oil to vinegar.

Answer 1

Answer:

Step-by-step explanation:

Set this up as ratio of vinegar to oil in fraction form:

$\frac{v}{o}:\frac{5}{10}$

That's what we're given.  If we are looking to find how much oil he needs if he's using 9 ounces of vinegar, then 9 goes on top with the vinegar stuff and x goes on bottom as the unknown amount of oil:

$\frac{v}{o}:\frac{5}{10}=\frac{9}{x}$

Cross multiply to get

5x = 90 and

x = 18

Which you probably could do without the proportions.  If he is using 5 ounces of vinegar and double that amount of oil, then it just makes sense that if he uses 9 ounces of vinegar he will double that amount in oil to use 18 ounces.