Concept:
For a cyclic group \(Z_n\), there is exactly one subgroup corresponding to each positive divisor of \(n\).
Therefore, the number of subgroups of \(Z_n\) is equal to the number of positive divisors of \(n\).
Step 1: Identify the group.
The given group is
\[
Z_{48}
\]
This is a cyclic group of order
\[
48
\]
Step 2: Prime factorize \(48\).
\[
48=16\times 3
\]
\[
48=2^4\times 3^1
\]
Step 3: Find the number of divisors.
If
\[
n=p_1^{a_1}p_2^{a_2}\cdots p_k^{a_k}
\]
then the number of positive divisors is
\[
(a_1+1)(a_2+1)\cdots(a_k+1)
\]
Here,
\[
48=2^4\times 3^1
\]
So the number of divisors is
\[
(4+1)(1+1)
\]
\[
=5\times 2
\]
\[
=10
\]
Step 4: Final conclusion.
Since \(Z_{48}\) is cyclic, the number of subgroups is equal to the number of divisors of \(48\).
Therefore,
\[
\boxed{10}
\]