How to Answer Multi-Source Reasoning Questions, Part 2
In the first part of this article, we took a look at how to read MSR passages and take some light notes. We finished off with a problem—now let’s talk about the solution! (Note: click on the link earlier in this paragraph; you’re going to want the tab text when reading through the solution.)
Here’s the problem again:
“Based on the information in the passage and tables, it can be determined that the average monthly meat consumption, in pounds, by the residents of Barras in the AD 1000s was which of the following?
“(A) 9,600
“(B) 10,000
“(C) 16,000
“(D) 17,400
“(E) 18,000”
How did it go? Our first task is to figure out where to go. Which tab is likely to be most useful in answering this question? They ask about meat consumption and also specify Barras in the AD 1000s.
Both tables (in tabs 2 and 3) talk about Barras and meat consumption, but this question asks about pounds—that sends us to tab 3.
Read the key up at top. The table shows average monthly meat consumption (good, that’s what we want!) in pounds for a 4-person family. We want pounds. Do we want a 4-person family?
Nope. The question asks about the total consumption in pounds for the residents of Barras. We’re going to need to do a little calculating here.
In the 1000s, Barras’s average monthly consumption per 4-person family was 160 pounds. Per person, then, consumption was 160 /4 = 40 pounds. Hmm, now what?
We need to know the total number of residents in Barras in the 1000s. Where did they tell us that?
Right! Tab 1 gave some information about population at the end of the paragraph about Barras. The passage says that there were 400 residents, on average, in the AD 1000s.
400 residents multiplied by 40 pounds per resident is a total of 16,000 pounds.
The correct answer is (C).
What did you learn about MSRs from this problem? I think there are 3 key takeaways, which I list at the end of this article; try to come up with your own before you read them.
Let’s try another problem from this MSR; give yourself about 1.5 to 2 minutes total to answer all three parts of this problem.
“Assume that any increase of 5% or more from one century to the next in the amount of a given food consumed by Barras residents is due primarily to a corresponding increase in imports of that food into Barras from other villages. Given this assumption and the information provided, for each of the following, select Yes if it describes a food likely imported by Barras during times of increased food consumption. Otherwise, select No.
“Yes No Meat from Agna from the AD 500s to the AD 600s Meat from Agna from the AD 800s to the AD 900s Grain from Cussaia from the AD 600s to the AD 700s”
This problem is complicated. First, note that Barras is the focus of the problem. If the consumption of a particular food in Barras increased by 5% or more from one century to the next, then we’re supposed to assume that this increase was primarily due to importation of that food—that is, Barras wasn’t producing this increase itself.
Each question mentions a particular timeframe. The first two deal with meat from Agna; the third deals with grain from Cussaia.
First, we have to figure out whether there was a 5% or greater increase of the relevant food type during the given time period. Tab 2 gives data on food consumption in Barras.
What happened with Barras meat consumption from the 500s to the 600s? Hmm. I have no idea—the 500s are not included in the table! Great, we don’t have to figure anything else out. The answer to the first statement must be No. (Note: tab 1 also says that Agna wasn’t established until around AD 800, so it couldn’t have been responsible for providing meat to Barras before then.)
What about meat consumption from the 800s to the 900s? Wow, consumption went from 15% to 30%. That’s definitely more than a 5% increase, so this statement potentially qualifies. Would that meat potentially have come from Agna, specifically?
Check tab 1 or your notes. Yes, Agna traded meat to Barras in general (and Cussaia did not), so this more-than-5% increase likely did come from Agna. The answer to the second statement is Yes.
Now, we’re switching both time frames and food type: grain from the 600s to the 700s. Consumption went from 10% to 15%, which is a 5% increase. This statement potentially qualifies. Would that grain have come from Cussaia?
Check tab 1 or your notes. Yes! Cussaia did produce grain (and Agna did not). The answer to the second statement is Yes.
The answers to the three statements are No, Yes, and Yes, respectively.
Key Takeaways for Multi-Source Reasoning problems
(1) Job #1 is to figure out where to look for the needed information. Note that you may have to look at 2 (or even all 3) tabs! If your notes didn’t help you to know where to look, then figure out how you could have organized better or jotted down a few more details in order to know where the main pieces of information could be found again.
(2) When pulling data from a table or chart, make sure to read the key first. In the first problem, the “per 4-person family” detail was key.
(3) Note that both problems revolved around dietary patterns and trading relationships—exactly what the very first sentence of the first tab indicated would be the focus of the MSR! Concentrating on that information during the read-through, and organizing our notes by tab, gave us the higher-level details we needed in order to know where to look to answer the questions.
* GMATPrep® questions courtesy of the Graduate Management Admissions Council. Usage of this question does not imply endorsement by GMAC.