Sequence And Series Question 427

Question: If the positive integers a, b, c, d are in AP, then the numbers abc, abd, acd, bcd are in

Options:

A) HP

B) AP

C) GP

D) None of the above

Show Answer

Answer:

Correct Answer: A

Solution:

[a] Given, a, b, c, d are in A.P.
$ \Rightarrow ,\frac{1}{a},\frac{1}{b},\frac{1}{c},\frac{1}{d} $ are in H.P.
$ \Rightarrow ,\frac{1}{d},\frac{1}{c},\frac{1}{b},\frac{1}{a} $ are also in H.P. Now, multiply each term by abed. $ \frac{abcd}{d},\frac{abcd}{c},\frac{abcd}{b},\frac{abcd}{a} $ $ abc,abd,acd,bcd, $ are in H.P.