A man sold 20 articles for $50 and gained 20%. How many articles should he sell for $90 to incur a loss 20%?  Answers:
A) 45
B) 36
C) 40
D) 54
E) 48
Production cost per article: $50*(100%-20%) / 20 = $2.0   Required production costs for a loss of 20%: $90*(100% + 20%) = $108   Number of articles to be sold for $108 to incur a 20% loss: $108 / $2.0 = 54   Thus, solution 54 is correct.108 /  2.0= 
<gadget id="calculator">108 /  2.0</gadget>
<output>54</output>
54   Thus, solution 54 is correct.
<result>D</result>
A man sold 20 articles for $50 and gained 20%. How many articles should he sell for $90 to incur a loss 20%?