Question

Four numbers are in arithmetic progression. The sum of first and last term is 8 and the product of both middle terms is 15. The least number of the series is [MP PET 2001]
A) 4 B) 3 C) 2 D) 1

Answer 1

the series is 1,3,5,7
or 7,5,3,1 the least value is 1 option D

Answer 2

Answer:

Step-by-step explanation:

Take A.P. as (a-3d),(a-d),(a+d),(a+3d)

Given,

a-3d+a+3d=8

2a=8

a=4

(a-d)(a+d)=15

a*2-ad+ad-d*2=15

16-15=d*2

d=1

Sub. a,d values in here

(a-3d),(a-d),(a+d),(a+3d)

(4-3),(4-1),(4+1),(4+3)

=(1),(3),(5),(7)

=The least no. In this series is 1

Hence option D is correct