What is the total possible no. of ways that $4$ shoes can be chosen from $5$ pairs of shoes such that none of the shoes chosen forms a pair ?
So say the shoes are $(A_1,A_2); (B_1,B_2); (C_1,C_2);(D_1,D_2);(E_1,E_2)$. I have to choose $4$ among the $A,B,C,D,E$ s such that no same letter appears. So one from each pair, so $2$ choices for each draw, giving $2^4$ choices, but this is multiplied with how many ways $4$ letters can be chosen from $5$ letters. Hence ${5\choose 4} \times2^4$ choices.
Is this correct ?
Please help
Yes that is perfectly correct answer and procedure.