1. **State the problem:** Jacob bought a total of 12 bottles of soda and juice. Each soda bottle has 25 grams of sugar, each juice bottle has 10 grams of sugar, and the total sugar is 240 grams. We need to find how many bottles of soda and juice he bought. 2. **Define variables:** Let $s$ be the number of soda bottles and $j$ be the number of juice bottles. 3. **Write the system of equations:** $$\begin{cases}s + j = 12 \\ 25s + 10j = 240\end{cases}$$ 4. **Solve the first equation for $j$:** $$j = 12 - s$$ 5. **Substitute $j$ into the second equation:** $$25s + 10(12 - s) = 240$$ 6. **Distribute and simplify:** $$25s + 120 - 10s = 240$$ 7. **Combine like terms:** $$15s + 120 = 240$$ 8. **Subtract 120 from both sides:** $$15s + \cancel{120} - \cancel{120} = 240 - 120$$ $$15s = 120$$ 9. **Divide both sides by 15:** $$\frac{15s}{\cancel{15}} = \frac{120}{\cancel{15}}$$ $$s = 8$$ 10. **Find $j$ using $j = 12 - s$:** $$j = 12 - 8 = 4$$ **Final answer:** Jacob bought 8 bottles of soda and 4 bottles of juice.