Question

1
Four number are in an AP. such that their sum is 54. If the product of the first and fourth terms is
162, then what is the product of the second and third terms of the A.P. ? ANS : 180
hint let the four numbers are a-3d, a-d, a+d, a +3d​

Answer 1

Sn=54

When n=4,

S4=4/2[2a+(4-1)×d]

54=2×(2a+3d)

27=2a+3d ....... (1)

........

t1×t4=162

54=n/2(t1×t2)

27=162n