Question 167204
lets call the number of adults a and the number of  children c.

so the total adults plus the total children equals 40 or a+c=40 or c=40-a

also we know that 8a+5c=272

substituting c's value in the 1st equation into the 2nd equation we get

8a+5(40-a)=272---->lets distribute that left side---->8a+200-5a=272

now lets combine like terms on either side of the equals sign.

{{{3a=72}}} {{{a=24}}}

so we have {{{highlight(24-adults)}}}
and c=40-a(24)={{{highlight(16-children)}}}