Answer to Question #322469 in Linear Algebra for Kenth Smith

Question

A man rows 12 miles downstream on a river in 2 hrs. He requires another 3 hrs. to row back to his starting position. Find the speed of the current and the rate the man can row in still water.

Answer 1

$v-rate\,\,of\,\,man\\u-speed\,\,of\,\,the\,\,current\\\left\{ \begin{array}{c} 2\left( v+u \right) =12\\ 3\left( v-u \right) =12\\\end{array} \right. \Rightarrow \left\{ \begin{array}{c} v+u=6\\ v-u=4\\\end{array} \right. \Rightarrow \left\{ \begin{array}{c} v=5\\ u=1\\\end{array} \right.$