Question

which terms of the AP : 3,8,13,18,......, is 78? ​

Answer 1

Answer:

Step-by-step explanation:

given,a=3 d=5

Let \:n^{th} \: term = 78

\implies a+(n-1)d=78

\implies 3+(n-1)\times 5 = 78

\implies (n-1)\times 5 = 78-3

\implies (n-1)\times 5 = 75

\implies n-1= \frac{75}{5}

\implies n-1=15

\implies n=15+1

\implies n=16

Therefore,

16th term in given A.P is 78

Answer 2

Answer:

16

Step-by-step explanation:

seq: 3,8,13,18........,78

a=3

c.d=5

let 78 be a(n)th term

$a(n) = a + (n - 1)d$

So,

3+(n-1)5=78

(n-1)5=78-3

5n-5=75

5n=75+5

5n=80

n=80/5

n=16

The 16th term is 78