Hi All,
We're told that a school supply store sells only one kind of desk and one kind of chair, at a uniform cost per desk or per chair. The total cost of 3 desks and 1 chair is TWICE that of 1 desk and 3 chairs. We're asked - the total cost of 4 desks and 1 chair is how many times that of 1 desk and 4 chairs. This question is ultimately about ratios - and you have to do a little Algebra to work through it.
The information that we're given can be translated into the following equation:
3D + C = 2(D + 3C)
We can then do a couple Algebra steps to simplify this equation:
3D + C = 2D + 6C
D = 5C
We now know that 1 desk is the same price as 5 chairs. With this information, we can substitute in to the given question:
Cost of 4 desks and 1 chair = 4D + 1C = 4(5C) + 1C = 21C
Cost of 1 desk and 4 chairs = 1D + 4C = 1(5C) + 4C = 9C
21C/9C = 7/3
Final Answer: E
GMAT assassins aren't born, they're made,
Rich
