Question

Let the positive numbers a, b, c, d be in A.P. Then abc, abd, acd, bcd are

• A. NOT in A.P./G.P./H.P.
• B. in A.P.
• C. in G.P.
• D. H.P.

Answer 1

Answer: (D)

$a,b,c,d\to$ A.P.
Divinding by abcd $\frac{1}{bcd},\frac{1}{acd},\frac{1}{abd},\frac{1}{abc}\to$ A.P.
$\therefore abc,abd$, acd, bcd $\to$ H.P.