How many distinct arrangements are possible for the letters of “STRESS”? (S appears 3 times; T, R, E appear once each.)

Introduction / Context:
We handle repeated letters by dividing n! by the product of factorials of letter multiplicities. “STRESS” has 6 letters with S repeated thrice.

Given Data / Assumptions:

• Total letters = 6; multiplicities: S × 3; T,R,E × 1 each.

Concept / Approach:
Compute 6! / 3! because only S repeats (three times).

Step-by-Step Solution:

Verification / Alternative check:
Any alternative count should match this canonical multiset-permutation formula.

Why Other Options Are Wrong:
720 ignores repeats; 360 and 240 reflect partial or incorrect divisors.

Common Pitfalls:
Miscounting repeated letters or dividing by extra factorials for letters that do not repeat.

Final Answer:
120