If the sales tax reduced from 3 1/2 % to 3 1/3%, then what difference does it make to a person who purchases an article with market price of Rs. 7800 ? Choose the correct answer: A) 11 B) 13 C) 14 D) 18 E) 10

Rationale: "required difference = [ 3 ½ % of rs . 7800 ] – [ 3 1 / 3 % of rs . 7800 ] = [ ( 7 / 20 - ( 10 / 3 ) ] % of rs . 7800 = 1 / 6 % of rs . 7800 = rs . [ ( 1 / 6 ) 8 ( 1 / 100 ) * 7800 ] = rs . 13 . answer is b ."
Answer: B