Answer:
number o students bought pennants = 18
number of student bought fancy ones=12
Step-by-step explanation:
Let x be the number o students bought pennants
and y be the number of student bought fancy ones
total 30 students
[tex]x+y= 30[/tex]
[tex]y=30-x[/tex]
Plain pennants cost $4 each and fancy ones cost $8 each.
[tex]4x+8y=168[/tex]
Substitute 30-x for y in second equation
[tex]4x+8(30-x)=168[/tex]
[tex]4x+240-8x=168[/tex]
[tex]240-4x=168[/tex]
Subtract 240 from both sides
[tex]-4x=-72[/tex]
divide both sides by -4
x=18
[tex]y=30-x[/tex]
[tex]y=30-18= 12[/tex]
number o students bought pennants = 18
number of student bought fancy ones=12
