Question 97910
Uhm...

Woman -> {{{6mi/h}}} = {{{cross(6)mi/cross(60)min}}} = {{{1mi/10min}}}
Bikeman -> {{{12mi/h}}} = {{{cross(12)mi/cross(60)min}}} = {{{1mi/5min}}} = {{{2mi/10min}}}

In 10 minutes the woman will have walked 1 mile, while the bikerman will have walked 2 miles. As they're walking in opposite directions, they'll be three miles apart.