Answer: 17 campers attended last year
Step-by-step explanation:
Let x be the number that attended last year.
The number of campers this year (23) is equal to 2 times the number of last year (x), minus 11.
23 = 2x – 11
23 + 11 = 2x
34 = 2x
34/2 = x
17 = x
