Question 1129058
{{{ 7/2 }}} is her rate of sketching
[ number of strips sketched ] / [ rate of sketching them ] = { time to sketch them ]
{{{ 21 / (( 7/2 )) = 21*( 2/7 ) }}}
{{{ 21 / (( 7/2 )) = 6 }}}
6 hrs