Students in the 7th and 8th grade at Imawinner Middle School are going on a field trip to the planetarium. If a student actively participates in the engagement activities at the planetarium, they are entered into a raffle to win a free lunch from their favorite restaurant. The table below shows the number of students in each grade and homeroom who engaged in the activities.
Homeroom A | Homeroom B | Homeroom C
7th Grade | 8 | 10 | 7
8th Grade | 9 | 10 | 9
What is the probability the winner is NOT in Homeroom B? (1 point)
A. 10/53
B. 20/53
C. 33/53
D. 20/53
To find the probability that the winner is NOT in Homeroom B, we need to add up the number of students in all the other homerooms (Homeroom A and Homeroom C) who are entered into the raffle.
Homeroom A (7th grade): 8 students
Homeroom A (8th grade): 9 students
Homeroom C (7th grade): 7 students
Homeroom C (8th grade): 9 students
Total number of students in all homerooms except Homeroom B = 8 + 9 + 7 + 9 = 33
Total number of students in all homerooms = 8 + 10 + 7 + 9 + 9 + 10 = 53
Therefore, the probability that the winner is NOT in Homeroom B is 33/53 or option C.