I got the comments from a journal where two reviewers asked almost similar query. How do I respond to it? Can I answer it at one place and in the other place, I can briefly describe the answer and say a more detailed response is presented before in page so and so..
This is very common and there's no need to overthink it. Answer the question for Reviewer 1, and then when listing and answering Reviewer 2 questions, write out the question and answer "This is the same point as question 3 from Reviewer 1, and is addressed in my response there."
You should be very sure you've addressed the question clearly and thoroughly, because if multiple reviewers flag it then there's some problem you need to sort out.
What I do in such a circumstance is to enumerate my comments, answer the query in detail only once, and refer to the comment instead of answering more than once:
Please see Comment #3 for a discussion of foo bar.
Reviewers work separately, and are liable to come up with the same comments/questions. If you are supposed to address them all in one swoop, just make a list of "Question 4 by A/3 by B: Answer". Or write answers to the questions of A and B separately, noting any overlaps.
Normally, you would compile the questions and comments of all reviewers into a complete list, and merge matching questions while you're at it. Then, you can address the points raised by decreasing order of importance, so if you run out of space (depending on the field, messages to reviewers can be restricted in length, e.g. to a maximum of a few thousand or so words), you can skip the less important topics. Instead, you can concentrate on the most important questions (especially the ones that you can answer only in the message to the reviewers, but not directly in the paper), as well as on misrepresentations/misinterpretations of your work by reviewers.
Among the points addressed, you can briefly remark which reviewer they were raised by (for the sake of brevity, abbreviations like R1, R2, R3, etc. will be understood in my experience). For points raised by several rewievers, simply mention all of those who did.
We agree with R3 that the rotation speed of the outer element needs to be adjustable and have added an according remark to the paper. The maximum and minimum rotation values are indeed at 0 and 42, as surmised by R1 and R4. We have integrated this information into Table VI.
I prefer to classify my response to the reviewers based on issues rather than based on the reviewers themselves. Let's say reviewer 1 and reviewer 2 question the validity of your analysis, and reviewer 2 and reviewer 3 ask why you did not adopt approach X. My rebuttal would look like this:
===== START OF REBUTTAL =====
Validity of the analysis (R1,R2)
R1 and R2 question the validity of the analysis, ... [here goes your answer]
Approach X (R2,R3)
R2 and R3 question why we did not employ approach X, the reason is ... [here goes the answer]
===== END OF REBUTTAL =====
In general it is good practice to remind the reviewers of the issues you raised. It could be the case that by the time the reviewer reads your rebuttal, he/she had already forgotten a lot of details. Additionally "tagging" the reviewer grabs his/her attention to that section, assures the reviewer that you addressed the point that was raised by him/her and will help you save the usually limited space to address as much issues as possible.
I would also try to prioritize the issues raised by the reviewers and address the most important ones first.