Question 389335
400 + (n-1)(-5) = 322 + (n-1)(-3);
400-5n + 5 = 322 - 3n + 3;
405 - 5n = 325 - 3n;
80 = 2n;
n = 40,
n - 1 = 39, the number of weeks after which they will weigh the same.