Reena took a loan of $. 1200 with simple interest for as many years as the rate of interest. If she paid $ 192 as interest at the end of the loan period, what was the rate of interest?
Choose the correct choice from the following choices.
A) 3.6 B) 6 C) 4 D) can not be determined E) none of these

Rationale: "let rate = r % and time = r years . then , 1200 x r x r / 100 = 192 12 r 2 = 192 r 2 = 16 r = 4 . answer : c"
Answer: C