Hi All,

While this question is based around 'system' algebra, the numbers involved are relatively small, so even if you are not 'great' at that type of math, you can still get to the correct answer with a bit of note-taking and 'brute force.'

We're told that Barbara buys 2 types of books (novels and comic books) and spends a total of $95. We're asked how many NOVELS Barbara buys...

1) Barbara pays $5 per novel and $10 per comic book.

'5' and '10' are relatively easy numbers to work with. Since the total spent is $95, you should be able to see (and prove) that there are multiple possibilities...

For example....

1 novel and 9 comic books = $95

3 novels and 8 comic books = $95

5 novels and 7 comic books = $95

Etc.

From this work, you should also recognize a pattern - you can 'trade' one comic book for two novels and spend the same amount of money...

Fact 1 is INSUFFICIENT

2) Barbara bought a total of 11 books.

With the prices of each type of book, this information is not enough to tell us how many Novels she bought.

Fact 2 is INSUFFICIENT

Combined, we know

Total Spend = $95

Novels = $5 each and comic books = $10 each

Total books = 11

From the work that we did in Fact 1, we can use the pattern we discovered to avoid doing any more work.

1 novel and 9 comic books = 10 total books

3 novels and 8 comic books = 11 total books

5 novels and 7 comic books = 12 total books

Etc.

Since 'trading' one comic book gets us 2 novels, the total number of books will vary based on the total number of comic books. The ONLY combination that gives us 11 total books is when there are 3 novels and 8 comic books, so the answer to the question MUST be '3.'

Combined, SUFFICIENT

Final Answer:

GMAT assassins aren't born, they're made,

Rich

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