Answer: q + 10
Step-by-step explanation: considering the numbers a, b, c, d, e and f
Mean would be
a+b+c+d+e+f/6 = q (1)
Considering we remove f, the new mean would be
a+b+c+d+e/5 = q-2 (2)
From (1):
a+b+c+d+e+f = 6q
from (2)
a+b+c+d+e = 5(q-2)
a+b+c+d+e = 5q - 10
Substituting (2) in (1)
a+b+c+d+e+f = 6q
5q - 10 + f = 6q
f = 6q - 5q + 10
f = q + 10