Question 482601
12/(8-n)+16/(8+n)=8
12(8+n)+16(8-n)=8(64-n2)
96+12n+128-16n=512-8n2
8n2-4n-288=0
2n2-n-72=0
*[invoke quadratic "x", 2, -1, -72 ]
n=6.25520607473216 or -5.75520607473216
Throwing out the negative answer, we get the speed of the current to be 6.25520607473216 mph..