Answer:
each role of streamers cost $2.5
each party hat cost $1.50
Explanation:
Let 's' represent rolls of streamers and 'h' represent party hats
Lets form an equation first
=>For three rolls of streamers and 15 party hats cost $30.
3s + 15h = 30
s= (30-15h)/3 ----> eq(1)
=>For 2 rolls of streamers and 4 party hats cost $11.
2s + 4h = 11
s= (11 -4h)/2 ----> eq(2)
Lets equate eq 1 and 2 in order to find 'h'
(30-15h)/3= (11 -4h)/2 ---->(applying cross multiplication)
60 - 30h = 33 - 12h
60-33 = 30h -12h
27 = 18 h
h= 27/18 => 1.50
therefore, each party hat cost $1.50
substitute above value in eq 1
(1)=> s= (30-15h)/3
s= 30-(15 x 1.5) / 3
s= 2.5
Therefore, each role of streamers cost $2.5