Let's call the time he spent feeding the pigs after breakfast [tex]b[/tex] and the time he spent feeding the pigs in the evening [tex]e[/tex]. Using the information in the problem, we can say that [tex]e = b - 3[/tex], since he spent 3 minutes less than the amount of time at breakfast, which is [tex]b[/tex].
We can also say that [tex]e + b = 15[/tex], since he spent 15 minutes each day in total feeding the pigs. If we substitute in what we found for [tex]e[/tex], then we can find the equation [tex](b - 3) + b = 15[/tex], which we can simplify, as shown below:
[tex](b - 3) + b = 15[/tex]
[tex]2b - 3 = 15[/tex]
[tex]2b = 18[/tex]
[tex]b = 9[/tex]
We have found that he spent 9 minutes after breakfast feeding the pigs. We can find [tex]e[/tex] by substituting in what we found for [tex]b[/tex] into our earlier equation:
[tex]e = b - 3[/tex]
[tex]e = 9 - 3[/tex]
[tex]e = 6[/tex]
He spent 9 minutes feeding the pigs after breakfast and 6 minutes feeding the pigs in the evening.
