what error did they make?

Question

a class writes the equations n+n+1+n+2=87 to solve the following problem. the sum of 3 consecutive odd integers is 87. Find the three integers.

Answer 1

n, n+1, and n+2 represent consecutive integers

n, n+2, n+4 represent consecutive odd integers

n+n+2+n+4=87

3n+6=87

3n=87-6

3n=81

n=81/3

n=27, n+2=29, and n+4=31

here's a simple arithmetic solution...

87/3=29

29-2=27 and 29+2=31

27, 29, 31 are the integers

if you have 3 consecutive odd integers the middle one is the mean of the 3 integers, so you don't even have to use algebra