Question 936028
let x be the total allowance Jon started with
  allowance spent on baseball cards  =  (1/3)*x
     allowance spent on base ball souvenirs   =  (1/4)*x 
   allowance spent on baseball ticekt   =  (3/8)*x
   remaining allowance   = total allowance - amount spent on baseball cards - amount spent on baseball souvenirs - amount spent on baseball ticket
                      ={{{x- (1/3)x - (1/4)x -(3/8)x }}}
                       = {{{ x/1-x/3-x/4-3x/8}}}
L.c.M of denominators ( 1,3,4,8  ) is  24
                        hence multiply each term with (24/24)
                         ={{{ x/1 *(24/24) -x/3 *(24/24)-x/4 *(24/24)-(3x/8)*(24/24)}}}
                        = {{{ (24x - x*8 -x*6-3x*3)/24}}}
                        ={{{ (24x-8x-6x-9x)/24}}}
              ={{{ x/24}}}
but amount remaining is $ 5
  hence  {{{ x/24  = 5}}}
 multiply with 24 on both sides
  {{{  (x/24)* 24   =5*24 }}}
      {{{ x= 120 }}}
Result : Allowance he started with is $120