Explanation:

- Statement 1: "Let we" - Incorrect usage. It should be "Let us" or "Let's". This is a grammatical error.

- Statement 2: "all solve" - After correction of Statement 1, this remains correct in context.

- Statement 3: "this problem" - Correct grammar and usage.

- Option 1: Incorrect, as Statement 1 contains a grammatical error.

- Option 2: "all solve" is correctly used, so no error here.

- Option 3: Statement 3 is correct; no error here.

- Option 4: Incorrect, as this implies no errors, which is not true.

The correct answer is: Option 1

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