Answer:
The number will be -63
Step-by-step explanation:
Here, we want to give the number of the chosen 25th student
We can see that the numbering follows an arithmetic sequence where a = 9 and d which is the common difference is (6-9) = -3
Mathematically, we can calculate the nth term using the equation below;
Tn = a + (n-1)d
in this case, n = 25, a = 9 and d = -3
So we have
Tn = 9 + (25-1)-3
Tn = 9 -3(24)
Tn = 9-72
Tn = -63
