For n identical capacitors connected in series, the equivalent capacitance is, Cs=
C
n
Similarly, for m identical capacitors connected parallel to each other, the equivalent capacitance is, Cp=mC Assuming the two combinations are connected in series, the net capacitance,
1
Cnet
=
1
mC
+
n
C
=
11
10
µF...(∵Cnet =
10
11
µF) ∴ for C=2µF,
11×2
10
=
1
m
+n ∴
1
m
+n=
11
5
..... (i) Substituting the values for m and n in equation (i) from each option, the correct answer can be found to be (A).