Answer:
24 tests
Step-by-step explanation:
Since 32 equals one hour and one hour is the total, we can see that 15 minutes equal 1/4, or 25%, 30 minutes equal 2/4, or 50%, and 45 minutes equal 3/4, or 75%. So, we can divide 32 by 4 to find out 1/4, or 25%, which equals 8. You can then multiply 8 by the number of fourths in 75% or 45 minutes, which is 3. 8 x 3 equals 24, so Mrs. Wilbur can grade 24 tests in 45 minutes.