The product of three numbers in G.P. is 125 and the sum of their products taken in pairs is Find them.
The sum of three numbers in G.P. is 21 and the sum of their squares is 189. Find the numbers.
Let a - d, a, a + d be three numbers in A.P. Since their sum is 21
∴ a - d + a + a + d = 21
3a = 21 a = 7
∴ Numbers are 7 - d, 7, 7 + d
It is given that if the second number is reduced by 1 and third is increased by 1 then resulting three numbers form G.P.
∴ 7 - d, 7 - 1, 7 + d + 1 are in G.P. or 7 - d, 6, 8 + d are in G.P.
(8 + d) (7 - d) = 36
56 - 8d + 7d - d2 = 36
d =
When a = 7 and d = 4, numbers are 7 - 4, 7 + 4 or 3, 7, 11
when a = 7 and d = -5, numbers are 7 - (-5), 7, 7 - 5 or 12, 7, 2