The phrase "inquired about whether" is correct and can be used in written English.
It is typically used when someone wants to ask about a specific piece of information or to confirm something. Example: "Mary inquired about whether the meeting would be rescheduled due to the snowstorm."
(Maybe it's that tourist mentality: I never inquired about whether the camels we rode through back roads and villages were insured, either).
Among them: that Mr. Haag referred to one plaintiff as "dirty bird," watched pornography at the office, and inquired about whether a plaintiff "groomed her pubic hair".
She expressed concern for what had happened in New York, and inquired about whether anyone from New Rochelle had been lost.
Department officials confirmed Thursday that they began exploring the possibility after Texas inquired about whether it could use funding for its firearms program.
Mr. Othman has also inquired about whether an official American DC-3 aircraft had been parked at the Ndola airfield that night.
When I inquired about whether a tenth grader could enter BASIS, the two schools I contacted did their best to make it appear that it would be impossible.
A government official and an official familiar with the work of the commission said the commission was also inquiring about whether other lawmakers got discounts in Las Vegas.
To inquire about its inverse, we inquire about whether there's a system, which when we cascade the accumulator with that system, which I'm calling its inverse, we get an impulse out.
Mr. Snowden's supporters, including some associated with the antisecrecy organization WikiLeaks, have approached officials in Iceland on his behalf to inquire about whether he might be granted asylum there.
The man explained that Bill Wilson was the founder of Alcoholics Anonymous and that members use the question "Are you a friend of Bill's?" to discreetly inquire about whether acquaintances are in AA. "I'm not," I replied.
