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)

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