1. **State the problem:** Given that $y$ varies jointly as $x$ and $z$, and $y=24$ when $x=3$ and $z=4$, find $y$ when $x=6$ and $z=5$. 2. **Write the formula for joint variation:** $$y = kxz$$ where $k$ is the constant of proportionality. 3. **Find the constant $k$ using the given values:** $$24 = k \times 3 \times 4$$ $$24 = 12k$$ $$k = \frac{24}{12}$$ $$k = 2$$ 4. **Use $k$ to find $y$ when $x=6$ and $z=5$:** $$y = 2 \times 6 \times 5$$ $$y = 60$$ **Final answer:** $$y = 60$$