Question

Which term of the AP:3,8,13,18,..….,is78

Answer 1

a=3. d=5

an= a+(n-1)d

78= 3+(n-1)5

78-3= 5n-5

75= 5n-5

75+5=5n

80=5n

n= 80/5

n= 16

16 th term is 78

Answer 2

Answer:

HEY MATE!

HERE IS YOUR ANSWER.

Given ,

a = 3 , d = 8- 5 = 3 , l = 78 ( where a = first term, d= common difference, l= last term )

l= a+ ( n- 1) d

78= 3+ ( n- 1) × 5

78 = 3 + 5n - 5

78 = 5n- 2

78 + 2 = 5n

80 = 5n

:. 5n = 80

n= 16

So, This term have 16 term.❣❣❣❣