Question

5th term is 24 and 24th term is 5.
Find 1st term Find the common difference

Answer 1

Answer:

Let second term of A.P is a2 and the fifth term of A.P is a5 .

a2=24, a5= 3, a1=? d=?

a2 = a1 +1d , a5 =a1+4d

a1+d=24 --------- (1)

a1+4d=3----------- (2)

From equation (1) solve a1 , a1= 24-d--------(3)

After that replace a1 I n equation (2) by a1= 24-d then , we get :-

24-d +4d=3 , 3d =3-24 , 3d= -21 , d=-7 .

To get a1 substitute d by -7 in equation (3)

a1= 24-d, d=-7

a1= 24-(-7) = 24+7= 31

Therefore, the first term of A.P is 31 and common difference is -7