Whispering Inc. has been using the services of San Bernadino Brokerage Company (SBBC) for the past six months. SBBC has informed Whispering Inc. that the geometric mean monthly return was 6.4 percent and that over the past six months Whispering Inc. earned 15.4 percent, 18.4 percent, -22.4 percent, 13.4 percent, -7.4 percent, and an unknown amount in the last month. e.g. 14.5125%.) Determine the missing return. (Round intermediate calculations to 6 decimal places, e.g. 1.251125 and the final