Question

An A.P. consists of 37 terms. The sum of the three
middle most terms is 225 and the sum of the past
three terms is 429. Find the A.P.​

Answer 1

middle most terms=37/2=18(approx)

so,middle terms will be ,17,18,19

now

a+16d+a+17d+a+18d=225

3a+54d=225

a+27d=75.......i)

last three terms are,37,36,35

a+36d+a+35d+a+34d=429

3a+105d=729

a+35d=243.....ii)

now

subtract ii) from i)

8d=168

d=21

now take out A,by putting value of D in i)

a+27×21=75

a=75-(27×21)

a=-492

now AP,will be,-492,-492+21,....