Question

The sum of first three number in an arithmetic progression is 18 if product of the first term and third term is 5times the commmon difference find the no

Answer 1

Answer:

Let first three numbers of A.P are (a-d), a and (a+d)

sum of the first three numbers = (a-d) + a +(a+d) = 3a = 18 or a = 6

product of first and third term = (a-d)(a+d) = a2 -d2 = 36 -d2 = 5d or d2 +5d -36 = 0 or (d+9)(d-4) = 0

hence d = 4 and three numbers are 2, 6, 10