If p, q and r are three unequal numbers such that p, q and r are in A.P., and p, r-q and q-p are in G.P., then p : q : r is equal to:
Given that p, q and r are in A.P.,
2q = p + r
p = 2q - r Eq -1
Given that p, r-q and q-p are in G.P.,
Let us assume the common ratio of k in G.P.
r-q = k(p) Eq -2
q-p = k(r-q) Eq -3
q-p = $$k^{2}$$(p) Eq -4
Substitute Eq-1 in Eq-3,
q-(2q-r) = k(r-q)
r-q = k(r-q)
So, k=1
From Eq -4, we get q=2p
Now substitute q=2p in Eq-1 we get r=3p
Hence, ratio of p:q:r = p:2p:3p = 1:2:3
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