I think backsolving is a good way to do this. Note that you can skip answer choice A because that would mean Brian has negative dollars!

Let's look at B, then. I would usually choose to start with C, but since $100 is easy to work with, I did that first.

If Jennifer has $100, Brian then has $40. If Jennifer gives up 1/5 of her money ($20), she'll have $80 and Brian will have $60.

Since Brian now has 25% less than Jennifer now has, B is the right answer.

Just create two eqs

J = 60 + B

(4J/5) x (3/4) = B + J/5

solve to get J = 100

in retrospect, I dont know why this question was so hard for me during the cat exam. Seems so easy.

tension gets to you when the clock is ticking happens to most of us.

yes the tension gets me an clouds my thinking. The question is very straightforward and not too challenging once you backsolve. Lesson learned..stay cool.