A ball is dropped vertically from a great height. Its velocity v is given by

v= 50-50e^(-0.2t), t greater or equal to 0.

Find the time required to fall 250 m.

So I have integrated the velocity function and obtained the distance function, as required in previous parts of the question and I have obtained a value of -250 for the constant of integration.

My current setup right now is

t+50e^(-0.2t)-10=0

but how do I solve for t???