Question

which term of ap is 78 from the given series 3,8,13,18

Answer 1

Hi Friend !!!

Here is ur answer !!!

a = 3

d =5

An = a+(n-1)d

78 = 3+5n-5

5n = 80

n = 80/5

n = 16

Hope it helps u :-)

Answer 2

AP = 3 , 8 , 13 , 18



Here,


First term ( a ) = 3


Common difference ( d ) = 5



Tn = 78


a + ( n - 1 ) × d = 78



3 + ( n - 1 ) × 5 = 78



3 + 5n - 5 = 78



5n = 80


n = 16


Hence,

16th term of the given AP will be equal to 78.