A solution of $5\%$ NaCl in water is flowing in a stainless steel pipe. To estimate the flow rate, one of yourcolleagues starts pumping a $30\%$ NaCl tracer solution into the pipe at a rate of $80$ ml s while youmeasure the concentration of NaCl downstream after the solutions are well mixed. If the downstreamNaCl concentration is $9\mathrm{.}5\%,$ use mass balance principles to determine the flow rate of the initial $5\%$ NaClsolution