Question

If sum of 10th term and 16th term of an arithmetic sequence is 78 calculate Itz 13th term

Answer 1

Answer:

39 is the answer for the given AP

Answer 2

$Let \: 'a' \:and \:'d' \: are \: first \:term \:and$

$Common \: difference \: of \:an \: A.P$

$\boxed{\pink{n^{th}\:term (a_{n}) = a+(n-1)d}}$

$Sum \: of \: 10^{th} \:term \:and \:16^{th} \:term$

$= 78 \: (given)$

$\implies a+9d + a + 15d = 78$

$\implies 2a + 24d = 78$

/* Dividing each term by 2 , we get */

$\implies a + 12d = 39$

$\implies a + (13 - 1 )d = 39$

$\implies a_{13} = 39$

Therefore.,

$\red{ 13^{th} \:term \:in \: given \:A.P} \green{=39}$

•••♪