Respuesta :
Let's call C the amount Manuel raises for charity.
Manuel objective is:
[tex]250\text{ }<=\text{ C <= 350}[/tex]Let's say that the money Manuel has to raise to get to his goal is G. Before he raises any money, we have G = C.
Now, his parents donate 70, so G = C - 70. Replacing in the first equation:
[tex]\begin{gathered} 250\text{ <= C <= 350 } \\ 250\text{ <= G + 70 <= 350} \\ 250\text{ - 70 <= G <= 350 - 70 (substract 70)} \\ 180\text{ <= G <= 280} \end{gathered}[/tex]And Manuel has to raise between 180 and 280 to get to his goal.
Since he plans to ask for 10 to every person he ask to contribute:
[tex]\begin{gathered} \frac{180}{10}\text{ = 18} \\ \text{and} \\ \frac{280}{10}\text{ = 28} \end{gathered}[/tex]Manuel has to make between 18 and 28 persons to contribute.
If P is the number of persons, and since they are all giving 10, we can write that as:
[tex]180\text{ <= 10}\cdot P\text{ <= 280}[/tex]If we want to take into account Manuel parents, we can write it as:
[tex]250\text{ <= 10}\cdot P\text{ + 70 <= 350}[/tex]This is point a answer.
