# GMAT Problem Solving Practice: The Solution

- Feb 3, 06:00 AM Comments [0]

Did you try out Friday's GMAT problem solving practice question? If not, give it a try before you look at the solution. Here's a reminder:

A theater charges \$12 for seats in the orchestra and \$8 for seats in the balcony.  On a certain night, a total of 350 tickets were sold for a total cost of \$3,320.  How many more tickets were sold that night for seats in the balcony than for seats in the orchestra?

• (A) 90
• (B) 110
• (C) 120
• (D) 130
• (E) 220

The first step in this problem is to translate the word problem into math.  You can write two equations based on the information in the question stem.  Call the balcony seats B and the orchestra seats R (avoid using the letter O as a variable because it looks like the number 0.) Now, you can write one equation based on the number of seats sold and one equation based on the amount of money made:

R + B = 350
12R + 8B = 3,320

Next, you need to combine these equations to solve for one of the variables.  Reorganize R + B = 350 in terms of B to get

B = 350 - R

and substitute (350 - R) in for B in the other equation.  This gives you:

12R + 8(350 - R) = 3,320

From here, you can solve for R as follows:

12R + 8(350 - R) = 3,320

12R + 2800 - 8R = 3,320

4R = 520

R = 130

Is that the correct answer? It's there, answer choice D. But no, that's not what the question is asking for!

Next, plug 130 in for R in the initial equation and solve for B:

130 + B = 350

B = 220

Is that the correct answer? It's also there, answer choice E. No, that's still not what the question is asking for!

Finally, you need to find out how many more balcony seats than orchestra seats there are by subtracting the two results:

220 - 130 = 90, which is answer choice (A).

Questions? Talk to us in the comments!

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