Final answer:
The total distance Rebecca ran during the first hour cannot be determined without more information about her running speed.
Step-by-step explanation:
The question is asking for the total distance in miles that Rebecca ran during the first hour of her run.
To find this, we need more information about Rebecca's running speed. We are given that 40 percent of runners ran at speeds of 7.5 miles per hour or less and 60 percent of runners ran at speeds of 7.5 miles per hour or more. However, we do not know Rebecca's specific speed.
Without knowing Rebecca's speed, we cannot determine the total distance she ran during the first hour. We need additional information or clarification to answer this question accurately.