Question Number 131744 by bemath last updated on 08/Feb/21
Answered by liberty last updated on 08/Feb/21
$$=\:\mathrm{C}_{\mathrm{3}} ^{\mathrm{7}} \:=\:\frac{\mathrm{7}.\mathrm{6}.\mathrm{5}}{\mathrm{3}.\mathrm{2}.\mathrm{1}}\:=\:\mathrm{35}\: \\ $$