NDA 2025
- Exam
- NDA
- Year
- 2025
- Subject
- Mathematics
- Chapter
- Sequences and Series
NDA 2025 · Mathematics · Sequences and Series
If p , 1 , q are in AP and p , 2 , q are in GP, then which of the...
If , , are in AP and , , are in GP, then which of the following statements is/are correct?
I. , , are in HP.
II. , , are in AP.
Select the answer using the code given below.
I. , , are in HP.
II. , , are in AP.
Select the answer using the code given below.
Options
- AI only
- BII only
- CBoth I and II
- DNeither I nor II
Correct answer
C. Both I and II
Step-by-step solution
Since , , are in AP, we have .
Since , , are in GP, we have .
For , , to be in HP, the middle term must be the harmonic mean of and , which is given by .
Substituting the values of and , we get .
Thus, , , are in HP. Statement I is correct.
By the definition of harmonic progression, if , , are in HP, their reciprocals , , must be in AP.
Thus, Statement II is also correct.
Both statements I and II are correct.
Answer: Both I and II
Since , , are in GP, we have .
For , , to be in HP, the middle term must be the harmonic mean of and , which is given by .
Substituting the values of and , we get .
Thus, , , are in HP. Statement I is correct.
By the definition of harmonic progression, if , , are in HP, their reciprocals , , must be in AP.
Thus, Statement II is also correct.
Both statements I and II are correct.
Answer: Both I and II