Answer
$$
2.40 \mathrm{\ m} / \mathrm{s}
$$
Work Step by Step
We use $A v=$ const. The speed of water is
$$
v=\frac{(25.0 \mathrm{cm})^{2}-(5.00 \mathrm{cm})^{2}}{(25.0 \mathrm{cm})^{2}}(2.50 \mathrm{m} / \mathrm{s})=2.40 \mathrm{m} / \mathrm{s}
$$
