ContourPlot[(((1+x/100)^150-1)/(x/100)) = (200000/1720)*(1+x/100)^(150-y), {x, 0.1, 3}, {y, 0, 50}]

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.