As given in the question,
The ratio of sand to gravel used for making a concrete walkway is
2 to 3.
Now, if we increase the quantity of one thing, the quantity of the second thing should also increase in the same proportion.
Now,
new quantity of sand = 8
new quantity of gravel = y
Using the above-mentioned definition, we can write:
![(2)/(3)=(8)/(y)](https://img.qammunity.org/2023/formulas/mathematics/college/w891hbfg2gamea1g0w0j9daald5siz9qzv.png)
![y\text{ = }(8)/(2)\cdot3](https://img.qammunity.org/2023/formulas/mathematics/college/nz5yvmbrf2dv7h2x1xrfybega6xazq3foz.png)
![y\text{ = 12}](https://img.qammunity.org/2023/formulas/mathematics/college/ozzhjdko8fv7vhrewlxa0uvrwh6rv72q4g.png)
Therefore, option B is correct.