Why are these two mathematically equal decimals different? [duplicate]

This question already has an answer here:

• How to properly compare decimal values in C#? 4 answers

[Test]
public void Calculation()
{
  decimal a = 400m;
  decimal b = 12m;
  decimal c = 2m;
  var result = a / b / c;

  Assert.AreEqual(result, 400m / 24m);
}

Test Outcome: Failed

Result Message:

Expected: 16.666666666666666666666666666m

But was : 16.666666666666666666666666667m

Why are these two decimals different?

What can I use instead of 400m / 24m to make it equal to result?