Question 938311
RT=D  rate time distance, uniform rates for travel basic rule.


Let c be speed of stream or current
Given 12 mph speed of goat if current in stream absent
Let t be time either direction



__________________speed_________time_________distance
Upstream__________12-c__________t____________16
Downstrm__________12+c__________t____________32


System of equations
{{{system((12-c)t=16,(12+c)t=32)}}}
Solve the system, a few (or more) algebra steps.


A good way to go is,
solve one equation for t, and substitute this into the other equation; and then solve this for c.  You might be first tempted to "simplify" the equations of the system but that might make more steps and more work.