I agree with my colleague regarding the Request for Admissions. Understand that a party can request admissions regarding any issue in controversy in a case. You are obligated to admit or deny the various statements; however, if you can indicate that you are unable to either admit nor deny a particular request if you indicate why you are unable to do so.
As to the interrogatories, while service of the interrogatories might technically be defective, since it is such an easy fix, it is generally not worth the aggravation of objecting to them and making the other party re-serve them correctly.
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A request for admission is deemed admitted unless, within 30 days after receiving them, you send either (1) a denial or (2) you give some explanation as to why, after a reasonable investigation of materials readily available to you, you are unable to admit or deny. If appropriate, you can object. If you object, the other side can file a motion to determine whether your objection(s) are valid and, if your objections are overruled, you would have to respond.
As for the interrogatories, I agree that, if you received them, you should respond.