If the sum of three consecutive terms of an increasing A.P. is 51 and the product of the first and third of these terms is 273, then the third term is
Let 3 consecutive terms A.P is a –d, a, a + d. and the sum is 51
So, (a –d) + a + (a + d) = 51
3a –d + d = 51
3a = 51
a = 17
The product of first and third terms = 273
So, (a –d) (a + d) = 273
a2 –d2 = 273
172 –d2 = 273
289 –d 2 = 273
d2 = 289 –273
d2 = 16
d = 4
Third term = a + d = 17 + 4 = 21