Question

Which term of the A.P. $3,8,13,.....$ is $248$?

Answer 1

Ans.

given A.P is

$3,8,13,.....$

first term of this A.P is $a_1=3$

second term of this A.P is $a_2=8$

common difference of an A.P is given by

$(i.e.,d=a_{n+1}-a_n)$

putting n=1 in above equation

$d=a_2-a_1=8-3=5$

hence common difference for this A.P is $d=5$

the nth term of an A.P is given by.

$a_n=a_1+(n-1)d$

$⟹248=3+(n-1)\left(5\right)$

$⟹248=3+5n-5$

$⟹5\times n=248+2$

$⟹5\times n=250$

$⟹n=\frac{250}{5}$

$⟹n=50$

hence $50$th term of this A.P is $248$