Your have a balance of $410 on one card and $510 on the other. Together (add) this is a balance of $920. Your total credit limit is $2000 (add the limits of each card).
That means you use

. Percent means "out of 100" so we wish to write this fraction with 100 in the denominator (the bottom). We do this by dividing the top (numerator) and bottom (denominator) by the same number. Here we use 20. That gives us
