Peter invests a sum of money and gets back an amount of $ 800 in 3 years . David invests an equal amount of money and gets an amount of $854 in 4 years. If both amounts were invested at the same rate (simple interest ) What was the sum of money invested ? Select the correct option:
A) 653	B) 664	C) 698	D) 744	E) 700

Rationale: "since both peter and david invested the same amount of money at the same rate , they would earn same interest per year . david invested for one year more than peter and hence he got interest amount for one more year . interest earned per year = amount received by david - amount received by peter = 854 - 800 = 54 interest earned for 3 years = 54 * 3 = 162 amount invested = 815 - 162 = 653 answer : a"
Answer: A