In the storage room of a certain bakery, the ratio of sugar to flour is 5 to 8, and the ratio of flour to baking soda is 10 to 1. If there were 60 more pounds of baking soda in the room, the ratio of flour to baking soda would be 8 to 1. How many pounds of sugar are stored in the room?Many problems on the GMAT lend themselves to algebraic solutions, but sometimes those solutions can elude students in the heat of the moment on the test. Let's use this example to illustrate a useful technique to use when the algebra eludes us and we're confronted with a word problem that asks for a specific value, in this case pounds of sugar, and provides answer choices that are in numeric order - Backsolving. First label your answer choices as referring to the sought after value as such:
Pounds SugarA. 600
B. 1200
C. 1500
D. 1600
E. 1750
Then, we can simply work through the constraints of the problem. To maximize efficiency try to estimate if you need a high or low value first and/or eliminate any logically impossible choices. If you are unable to do so, a good tactic is beginning with answer choice C, because based on the outcome of that test at a minimum you should be able to determine whether the proper value should be higher or lower.
C. 1500 > Set up a proportion of 1500/x = 5/8 to find that based on the given ratios there would be 2400 pounds of flour and subsequently 240 pounds of baking soda. Now, add 60 pounds to that 240 pounds to get 300 hypothetical pounds of baking soda. 2400/300 equals the 8/1 ratio dictated by the problem, so C is the correct choice and without needing any complex algebra.
For those of you who can do the algebra referenced in the other replies to this post, do it! Algebra is often the fastest way to solve a problem like this one. However, if you are having issues with the algebra on any long-winded word problems asking for a specific value such and the answer choices are numeric values in ascending or descending order, consider backsolving as an alternative approach!