john dana and douglas painted a room
they have combined effort so
john+dana+douglas=total room
total room=100%=1/1=1
so 1 whole=8/8 so
2/8 is painted by john so they don't need to paint that so
so
2/8+dana+douglas=8/8
subtract 2/8 frm both sides
dana+dogluas=(8-2)/8=6/8
dana+douglas=6/8
dana painted same as douglas so divide by 2
dana=douglas=3/8
so A is 6/8 or 3/4
B is 2/8+3/8+3/8=8/8 or 2/8+dana+douglas=8/8