Answer
$\langle3+\frac{5\sqrt 2}{2}, \frac{5\sqrt 2}{2} \rangle$
Work Step by Step
1. Assign vectors: the original velocity of salmon $\vec {v_1}=5cos45^{\circ}i+5cos45^{\circ}j=\frac{5\sqrt 2}{2}i+\frac{5\sqrt 2}{2}j$, the velocity of water $\vec {v_2}=3i+0j$
2. The true velocity of the fish is the sum of the two velocities above $\vec {v}=(3+\frac{5\sqrt 2}{2})i+\frac{5\sqrt 2}{2}j$
3. We can also write the results in the form of $\vec {v}=\langle3+\frac{5\sqrt 2}{2}, \frac{5\sqrt 2}{2} \rangle$
