Question Number 125182 by Mammadli last updated on 08/Dec/20
$$\boldsymbol{{How}}\:\boldsymbol{{many}}\:\mathrm{3}−\boldsymbol{{digit}}\:\boldsymbol{{numbers}}\:\boldsymbol{{divisible}}\:\boldsymbol{{by}}\:\mathrm{5}\:\boldsymbol{{can}}\:\boldsymbol{{be}}\:\boldsymbol{{made}}\:\boldsymbol{{using}}\:\boldsymbol{{the}}\:\boldsymbol{{numbers}}\:\mathrm{7},\mathrm{8},\mathrm{9},\mathrm{2},\mathrm{1},\mathrm{0}\:\boldsymbol{{without}}\:\boldsymbol{{repetition}}? \\ $$
Answered by bemath last updated on 08/Dec/20
$${AB}\mathrm{0}\:\Rightarrow\:{P}_{\mathrm{2}} ^{\:\mathrm{5}} \:=\:\frac{\mathrm{5}!}{\mathrm{3}!}\:=\:\mathrm{20}. \\ $$