the answer for this situation is simple. Dont answer if you do not know accrding to your own understanding. It is better you said to them "i am sorry i do not know the answer YET, but i will come back to you for the answer after i get the correct answer according to our holy Quran." . So when we said these we wont give bad impression for Islam for ourself give them some information that we are not actually have faith for our answer. If we muslim ourself does not know the answer why should we answer. I believe if you put it on hold and looking for the answer mostly internet you will find more answer and not only answer we can get proof as there is no mistake for the Quran 100%.
For example one most popular question about the Holy Quran.
"Quran says that Allah has made the earth for you as a carpet. This gives an indication that the earth is flat. Does this not contradict established modern science?"
Okey. For this question i will take the research answer by Dr. Zakir Naik. For confirmation it is not he answer that. He just only do research but the answer are answered by the Holy Quran. All the answer are in the Holy quran.. So these are the example of answer:-
There are 4 answer to solve the question..
1. Earth made as a carpet
The question refers to a verse from the Quran in Surah Nuh:
“And Allah has made the earth for you as a carpet (spread out).” [Al-Quran 71:19]
But the sentence in the above verse is not complete. It continues in the next verse, explaining the previous verse. It says: “That ye may go about therein, in spacious roads.” [Al-Quran 71:20]
A similar message is repeated in Surah TaHa:
“He Who has made for you the earth like a carpet spread out; has enabled you to go about therein by roads (and channels)....” [Al-Quran 20:53]
The surface of the earth i.e. earth’s crust is less than 30 miles in thickness and is very thin as compared to the radius of the earth which is about 3750 miles. The deeper layers of the earth are very hot, fluid and hostile to any form of life. The earth’s crust is a solidified shell on which we can live. The Quran rightly refers to it like a carpet spread out, so that we can travel along its roads and paths.
2. Carpet can also be spread on other than an absolute flat surface
Not a single verse of the Quran says that the earth is flat. The Quran only compares the earth’s crust with a carpet. Some people seem to think that carpet can only be put on an absolute flat surface. It is possible to spread a carpet on a large sphere such as the earth. It can easily be demonstrated by taking a huge model of the earth’s globe covering it with a carpet.
Carpet is generally put on a surface, which is not very comfortable to walk on. The Quran describes the earth crust as a carpet, without which human beings would not be able to survive because of the hot, fluid and hostile environment beneath it. The Quran is thus not only logical, it is mentioning a scientific fact that was discovered by geologists centuries later.
3. Earth has been spread out
Similarly, the Quran says in several verses that the earth has been spread out. “And We have spread out the (spacious) earth: how excellently We do spread out!” [Al-Quran 51:48]
Similarly the Quran also mentions in several other verses that the earth is an expanse: “Have We not made the earth as a wide expanse “And the mountains as pegs?” [Al-Quran 78:6-7]
None of these verses of the Quran contain even the slightest implication that the earth is flat. It only indicates that the earth is spacious and the reason for this spaciousness of the earth is mentioned. The Glorious Quran says: “O My servants who believe! Truly spacious is My Earth: therefore serve ye Me . (And Me alone)!” [Al-Quran 29:56]
Therefore none can give the excuse, that he could not do good and was forced to do evil because of the surroundings and circumstances.
4. Earth is geo-spherical in shape
The Quran mentions the actual shape of the earth in the following verse: “And we have made the earth egg shaped”. [Al-Quran 79:30]
The Arabic word Dahaha means egg shaped. It also means an expanse. Dahaha is derived from Duhiya which specifically refers to the egg of an ostrich which is geo-spherical in shape, exactly like the shape of the earth.Thus the Quran and modern established science are in perfect harmony.