$3\mathrm{.}25g$ of compost was digested, filtered and the extract made up to $250cm3\mathrm{.}25cm3$ of the sample solution was made up with increasing amounts of $Cu(1ppm)$ and made up to $50cm3$ and analysed by ICPMS. Calculate the $\%$ wt$/$wt of $Cu$ FV DF

$\backslash$table$[[$Vol of sample IV DF$,$Vol of $1$ppmCu$(cm3)C{V}_2{C}_1=1,$Abs,$],[25,0,0,0\mathrm{.}16],[25,2,0\mathrm{.}04,0\mathrm{.}228],[25,4,0\mathrm{.}08,0\mathrm{.}296],[25,6,0\mathrm{.}26,0\mathrm{.}364]]$