Question 861471
I'm not sure how you do it on a grid.
Look at the possible picks and list all of them first.
{{{RR=(2/4)*(2/4)=1/4}}}
{{{RB=(2/4)*(2/4)=1/4}}}
{{{BR=(2/4)*(2/4)=1/4}}}
{{{BB=(2/4)*(2/4)=1/4}}}
Those are the 4 possible choices in picking two balls.
So two consecutive Reds is one of the four possible choices.