Question

which of the term of AP. 3, 10, 17...
will be 84 more than its 13 th term​

Answer 1

Answer:

25 th term

Step-by-step explanation:

13 th term = a+(13-1)d

= a+12d

= 3+12*7 ( d= difference between terms)

=3+84

=87

which term will be 84 more than 13 th term

let that term be n th

=>n th term = 13th + 84

=>87+84

=>171

by formula, n th term = a+(n-1) *d;

=>171 = 3+(n-1)*7

=>171 = 3+7n-7

=>171 = -4+7n

=>171+4 = 7n

=>175 = 7n

=>n = 175/7

=>n = 25 th term

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Answer 2

Step-by-step explanation:

Given: A.P: 3,10,17....

To find: a13+84=an, n=?

In A P:

a=3,

d=second term-first term

=> 10-3=7.

Formula of nth term of an A.P:

$an = a + (n - 1) \times d$

=> A13=3+(13-1)×7

=> 3+12×7.

=> 3+84

A13=87.

An=a13+84

=> 87+84

=> 171.

171=3+(n-1)×7

171-3=(n-1)×7

168/7=n-1

24+1=n.

25=n.

It is 25th term of the A.P.