WILL GIVE THANKS, BRAINIEST, AND 5 STARS! PLEASE HELP!

Answer:
30
Step-by-step explanation:
C(n) = 5n, 0 ≤ n ≤10 You would use this formula because 6 is greater than 0 but less than 10.
C(n) = 5n, 0 ≤ n ≤10 ← You can just ignore the 0≤ n ≤10 part.
C(6) = 5(6) Input the value 6 as x.
C(6) = 30
The answer is that 6 shirts costs 30 dollars.