75 miles per hour first, you must find out how many miles were traveled in total by finding how many miles 3/5 of the journey is. we know 2/5 is 300 since the rest of the journey took that long so we can find 1/5 by taking half of that (150) and then multiplying it by 3 to get 450. 450 + 300 is 750 which is then the total amount. to find the miles traveled per hour you then want to divide the miles traveled by the number of hours, which is 10 (6+4). so you do 750 divided by 10 which gets you your final answer 75.
