Answer:- 1)The group rents 11 person tubes and 4 cooler tubes.
2) The two system of equations are
x+y=15
20x+12.50y=270
Explanation:-
Given: x represents the number of person tubes rented and y represents the number of cooler tubes rented such that

⇒
.........(1)
Cost of a person tube=$20
Cost of a cooler tube=$12.50
Total spending on tube lights=$270
⇒
...............(2)
Substitute the value of x in (2), we get

⇒
[Distributive property]
⇒
⇒
⇒
[Subtract 187.50 from both sides]
⇒
⇒
[Divide 7.50 on both sides]
Substitute x=11 in (1), we get

∴ The group rents 11 person tubes and 4 cooler tubes.