How to find a ratio with a negative number

In the first line, you had $100 in revenue for $5 cost; that's a 20:1 ratio (your example, post #18).

In the second line, revenue increased by 40% and cost decreased by 6.5% (your example, post #1). The new ratio is 29.9.

Which is a 49.7 percent year-over-year increase (post #6).