Question 1041971
Let {{{U[1]}}} and {{{U[2]}}} be the two non-defective pair of skates, and {{{D[1]}}} and {{{D[2]}}} the two defective pairs of skates.
Then the sample space is 
{ { {{{U[1]}}},{{{U[2]}}} }, { {{{D[1]}}}, {{{D[2]}}} },  { {{{D[1]}}}, {{{U[1]}}} },  { {{{D[1]}}}, {{{U[2]}}} },  { {{{U[1]}}}, {{{D[2]}}} },  { {{{U[2]}}}, {{{D[2]}}} } }.

The probability that they will both get a pair of skates that are not defective is then 1/6.