Respuesta :
Answer:
25 adults and 30 students
Step-by-step explanation:
Let x be the number of adults and y be the number of students that visited the museum in one day. Then
[tex]x+y=55.[/tex]
x adults pay $20x and y students pay $20·0.6·y (because the the admission fee was reduced by 40%, then the admissin fee bacame $20·(1-0.4)=$20·0.6 ).
Thus,
[tex]20x+20\cdot 0.6\cdot y=860.[/tex]
Therefore, you have to solve the system of two equations:
[tex]\left{\begin{array}{l}x+y=55\\20x+20\cdot 0.6\cdot y=860\end{array}\right.[/tex]
From the first equation [tex]x=55-y,[/tex] substitute it into the second one:
[tex]20(55-y)+20\cdot 0.6\cdot y=860,\\ \\1100-20y+12y=860,\\ \\-20y+12y=860-1100,\\ \\-8y=-240,\\ \\y=(-240):(-8),\\ \\y=30[/tex]
and
[tex]x=55-30=25.[/tex]