And because our constant K stays the same at the same temperature going this way, that means our rate is strictly dependent on our concentration. And because we said our concentration is at its maximum at the beginning at time equals zero, that means our rate going this way forward of X converting to Y is at its highest. What about the reverse rate of going from Y to X? Well, at the beginning we said we don't have any of the Y, our Y or concentration of our product is zero. And that means since this guy is zero for the reverse reaction, that means our rate going backwards is zero. And that makes sense because if none of the Y has formed yet, that means none of the Y can convert back to X.