A store reported total sales of $480 million for February of this year. If the total sales for the same month last year was $320 million, approximately what was the percent increase in sales?  Choose the correct choice from the following.
A) 2 % B) 17 % C) 50 % D) 65 % E) 83 %

Rationale: "new value – old value ) / old value x 100 we are given : february sales this year = 480 million february sales last year = 320 million we need to determine the percent increase between sales from last year to sales this year . thus , the new value = 480 million and the old value = 320 million . let ’ s plug them into our percent change formula . ( new value – old value ) / old value x 100 [ ( 480 – 320 ) / 320 ] x 100 = 50 % . the answer is c ."
Answer: C