Take a look at the following problems.
Data Sufficiency: What was Company X’s percentage profit in 2011?
1) The ratio of costs to profits for Company X was 3 to 1 in 2011.
2) Company X’s costs in 2011 were $360,000.
A recipe for punch calls for 4 parts seltzer to one part juice. If John wants to make 5 gallons of punch, how many 8 ounce cans of juice does he need (1 gallon = 128 ounces)?
Both these problems have something in common. We are given a ratio, but not the specific ratio that would be most useful to our calculation. In the first case, the percentage profit can be calculated at profit/revenue * 100 (remember revenue = profit + costs). In the second case, the ratio that would be most helpful to solving is the ratio of juice to punch, which we could then use to calculate how many ounces of juice we need. It is common for test takers to get stuck at this point not knowing how to get to the ratio needed, but with a little understanding of ratios, it is actually a rather simple task to convert from the given ratios to the ratios that would be most helpful.