Question 653163
  <pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi,
the complement of angle a{{{highlight(90-a)}}}  
is 20 less then half the supplement of angle a.{{{highlight(180-a)}}}
Question states***
{{{highlight(90-a) =(highlight(180-a))/2 - 20}}}  |Multiplying thru by 2 so as all denominators = 1
 180 - 2a = 180 - a - 40
    40° = a
and...
{{{50 = 140/2 - 20 = 70-20 = 50}}}