Luke53 wrote:How can I solve this system? (e = natural log)

The natural-log function is denoted by "ln(x)", where "x" is the argument of the log function. Are you perhaps referring to the natural exponential, approximately equal to 2.71828? If so, then...

Luke53 wrote:x * e ^ -(0.2/y) = 4 (1)

x * e ^ -(1/y) = 1 (2)

My understanding of the system is as follows:

. . . . .. . . . .You can solve each of these equations for "x=", and then set the results equal, giving you one equation in one variable. Take the natural log of each side, and solve for the value of y. Back-solve for x.

I haven't done the complete solution, but I've gone far enough to confirm the approximate value you've listed for y.