Final answer:
Shannon's race time is slower than Patti's and faster than Phan's, placing her just below the top 60% of speeds above 7.5 miles per hour and above the bottom 40% of speeds 7.5 miles per hour or less.
Step-by-step explanation:
To estimate Shannon's race time, we need to consider her speed relative to Patti and Phan. If Shannon ran slower than Patti but faster than Phan, then her time would be higher (slower) than Patti's but lower (faster) than Phan's. However, without specific times or speeds for Patti and Phan, we can't calculate an exact time for Shannon. But based on the provided information, 40 percent of runners ran at speeds of 7.5 miles per hour or less, and 60 percent ran at speeds higher than 7.5 miles per hour. If Patti is among the faster 60 percent and Phan is among the slower 40 percent, Shannon's speed, and therefore her time, must be just slower than the cutoff for the faster group (just below 7.5 miles per hour) and faster than the cutoff for the slower group (higher than the time corresponding to 7.5 miles per hour).