Question 1201639
{{{system(k+d=240,4k/5=d+k/5)}}}


{{{4k=5d+k}}}
{{{highlight_green(3k=5d)}}}


{{{highlight_green(k=240-d)}}}
{{{substitute}}}:


{{{3(240-d)=5d}}}
{{{720-3d=5d}}}
{{{720=8d}}}
{{{d=720/8=(10*24*3)/8=(10*3*8*3)/8}}}
{{{highlight(d=90)}}}