Capacity of the elevator is: 15 children OR 11 adults. If there are 7 children in the elevator how many adults can fit into the elevator?
I am not sure, but I got the answer as 5 adults can fit in the elevator.
I agree with your answer. It may error on the side of safety.
Seven children would be equivalent to 5.1333 adults.
Some may argue that that is five adults.
But safety requires that we use six adults.