A company that receives most of its orders by telephone conducted a study to determine how long customers were willing to wait on hold before ordering a product. The length of waiting time was found to be a variable best approximated by an exponential distribution with a mean length of waiting time equal to 3 minutes​ (i. e. the mean number of calls answered in a minute is​ 1/3). Find the waiting time at which only​ 10% of the customers will continue to hold. Round to one decimal place.