SAT Question 30db8f77: Probability And Conditional Probability answer and explanation with Desmos solution

It's given that there are a total of $275$ attendees and each attendee is assigned to either group A, group B, or group C. It's also given that if one of these attendees is selected at random, the probability of selecting an attendee who is assigned to group A is $0.44$ and the probability of selecting an attendee who is assigned to group B is $0.24$. It follows that there are $0.44\left(275\right)$, or $121$, attendees who are assigned to group A and $0.24\left(275\right)$, or $66$, attendees who are assigned to group B. The number of attendees who are assigned to group C is the number of attendees who are not assigned to group A or group B. In other words, the number of attendees who are assigned to group C is the total number of attendees minus the number of attendees who are assigned to group A and group B. Therefore, the number of attendees who are assigned to group C is $275-121-66$, or $88$.