One-fifth of the cost price, one-seventh of the marked price and one-sixth of the selling price are all equal. What is the gain or loss to the trader?	Options.
A) 120 %
B) 140 %
C) 162/3 %
D) 20 %
E) None
Sol.   CP/5 = SP/6 ⇒ SP/CP = 1.2 ⇒ 20% gain.   Answer 20 %
<result>D</result>
One-fifth of the cost price, one-seventh of the marked price and one-sixth of the selling price are all equal. What is the gain or loss to the trader?