Answer:
Alternative B - 7.
Step-by-step explanation:
Let
"a" be the number of sessions painted by a group of two students;
and
"b" be the number of sessions painted by a group of four students.
Since the number total of sessions is 23,
Also, since the total of students is 76,
We can isolate "a" in the first equation and substitute in the second to find b:
And, since a = 23 - b
Finally, how many more sessions are painted by 4-students group:
So, the 4-students group painted 7 more sessions.
Answer: Alternative B - 7.