Question

if the nth term of an ap is 3n-8 find its 24th term​

Answer 1

Given,

nth term of an AP =3n-8

To find,

24th term​

Solution,

As it is given,

nth term of an AP =3n-8

Using the formula,

nth term of an AP = a+(n-1)d

∴a+(n-1)d= 3n-8

⇒a+nd-d=3n-8

On rearranging, we get

dn + (a-d)= 3n + (-8)

On comparing both the sides.

dn= 3n and a-d = -8

∴d=3

On solving,

a-3 =-8

a= -8+3

∴a=-5

Now, 24th term = a+(24-1)d

On substituting values of a and d, we get

⇒24th term = -5 + (24-1)3

⇒24th term = -5 +(23)(3)

⇒24th term= 64

Hence, the 24th term is 64