It has been said that mathematics is "the language of business." But many MBA programs are moving away from the heavily analytical approaches that predominated several years ago and are giving increased emphasis to the "soft" areas of communication and interpersonal skills. That said, the quantitative elements of business studies have not gone away.
The actual level of mathematical knowledge that you'll need varies widely from program to program. Some schools expect you to have studied statistics before entering the program. Some will expect you to use calculus on a regular basis. Generally speaking, you should certainly feel comfortable with college algebra and brush up your quantitative skills if they're rusty.
