The price of a book is increased from $300 to $420. What is the % of increase in its price? Choose the correct choice from the following answers.
A) 10 %	B) 20 %	C) 40 %	D) 50 %	E) 60 %

Rationale: "explanation : change in the price = rs 420 â € “ rs 300 = rs 120 percentage of increase = change in the price initial price * 100 . percentage increase in price = ( 120 300 ) * 100 = 40 % c"
Answer: C