Final answer:
Regina read his novel for a total of 2.25 hours.
Step-by-step explanation:
To find the total number of hours Regina read his novel altogether, we need to multiply the number of nights by the time he read each night.
Regina read his novel for 3/4 of an hour each night for a total of 3 nights.
Therefore, the total time Regina read his novel is 3/4 * 3 = 9/4 = 2.25 hours.