Thirty years ago, Mr. and Mrs. Lopez purchased a house. On average, the value of the house has doubled every 6 years. If the house is worth \$320,000 today, what did they pay for it 30 years ago?
(A)\$5,000 (B)\$10,000 (C)\$64,000 (D)\$160,000 (E)\(\$320,000 \times 2^5\)
B