I need to find the total number of stores at University Mall, which I'll call x. I know that 18 out of 90 stores sell shoes at North Area Mall, so the ratio of shoe stores to total stores there is 18/90, which simplifies to 1/5. I also know that 9 out of x stores sell shoes at University Mall, so the ratio of shoe stores to total stores there is 9/x. Since the problem says that the same ratio holds true for both malls, I can set the two ratios equal to each other and solve for x. So I have 1/5 = 9/x, which I can cross-multiply to get x = 5*9, which is 45. Therefore, there are 45 stores at University Mall.


In the North Area Mall, 18 of the 90 stores sell shoes. If that same ratio holds true for the University Mall and 9 stores there sell shoes, how many stores are at University Mall?