Three numbers are in AP. If their sum is 27 and their product is 648, find the numbers.
To Find: The three numbers which are in AP.
Given: Sum and product of three numbers are 27 and 648 respectively.
Let required number be (a - d), (a), (a + d). Then,
(a - d) + a + (a + d) = 27 3a = 27
a = 9
Thus, the numbers are (9 - d), 9 and (9 + d).
But their product is 648.
(9 - d) × 9
(9 + d)= 648
(9 - d)(9 + d)= 72
81 – d2 = 72
d2 = 9
d =
3
When d=3 numbers are 6, 9, 12
When d= (3) numbers are 12, 9, 6
So, Numbers are 6, 9, 12 or 12, 9, 6.