(c + g)/6
where c is apartment cost and g is grocer's cost
c = 1 400
g = 654
c + g = 2 054
2 054 / 6 = 342.3 with the three being reacurring. As far as I'm aware, it's best to round up as it would be better is everyone paid an insignificant penny more than four people paying more in the first place, resulting in a final cost of 342.34.