Question 1050563


if set {{{B }}}contains {{{69}}} elements, {{{n(B)=69}}}

total number elements in either Set {{{A}}} or{{{ B}}}, then {{{n}}}({{{A}}} U {{{B}}}) ={{{107}}}


then {{{n}}}({{{A}}} U {{{B}}})-{{{n(B)}}} ={{{107-69}}}={{{38}}}

{{{38}}} is a number of elements that are only in {{{ A}}} but not in ({{{A}}} intersection {{{B}}})

since given that ({{{A}}} intersection {{{B}}})={{{13}}}, you add it to {{{38}}} and you will get {{{n}}}({{{A=38+13=51}}}

check:

{{{n}}}({{{A}}} U {{{B}}}) ={{{n(A) -n(B)-13=(51+69)-13=120-13=107}}}