Which term of the A.P. 4, 9, 14,… is 254 ?

Answer:

Given,

A.P is 4, 9, 14,…

a₁ = a = 4

a₂ = 9

Common difference, d = a₂ – a₁ = 9 – 4 = 5

a_n = a + (n – 1)d

a_n = 4 + (n – 1)5

= 4 + 5n – 5

= 5n – 1

Put, a_n = 254

5n – 1 = 254

5n = 254 + 1

5n = 255

n = 255/5

n = 51

51^st term of given A.P is 254.