Final answer:
Mikey spent 1 hour and 37.5 minutes doing homework in total.
Step-by-step explanation:
To find the total time spent doing homework, we need to add the time spent on mathematics and science homework.
Mikey spent 3/4 hour on mathematics homework and 7/8 hour on science homework.
To add these fractions, we need to find a common denominator. The common denominator of 4 and 8 is 8.
So, 3/4 is equivalent to 6/8, and 7/8 remains the same.
Now, we can add the fractions: 6/8 + 7/8 = 13/8 hour.
Since 13/8 is an improper fraction, we can simplify it to a mixed number. 13 divided by 8 is 1 with a remainder of 5.
So, the total time Mikey spent doing homework is 1 and 5/8 hour, which is equivalent to 1 hour and 37.5 minutes.