Sequences and Series 5 Question 14

5. Suppose four distinct positive numbers a1,a2,a3,a4 are in GP. Let b1=a1,b2=b1+a2,b3=b2+a3 and b4=b3+a4.

Statement I The numbers b1,b2,b3,b4 are neither in AP nor in GP.

Statement II The numbers b1,b2,b3,b4 are in HP.

(2008, 3M)

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Answer:

Correct Answer: 5. (c)

Solution:

  1. Let a1=1,a2=2,a3=4,a4=8

b1=1,b2=3,b3=7,b4=15

Clearly, b1,b2,b3,b4 are not in HP.

Hence, Statement II is false.

Statement I is already true.



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