Let n be the amount of pages of each type. Since pages of 1/4, 1/2 and full pages were bought in equal amounts, then the total amount of purchased paper is:

On the other hand, since each 1/4 page costs $200, each 1/2 page costs $350 and a full page $600, then the total amount of money spent on that is:

The total is also equal to $11,500. Then:

Then, substitute n=10 into the first expression to find the total amount of page space that was purchased:

Therefore, the total amount of space that was purchased was:
