Question

Find the sum to 200 terms of the series 2 + 5 + 7 + 6 + 12 + 7 + ....
A) 30,400
B) 30,200
C) 34,600
D) 38,400

Answer 1

Hey mate ^_^

=======
Answer:
=======

We will have a total of 100 terms of the nature:

$(2 + 5) + (7 + 6) + (12 + 7)$

$7, 13, 19,....$

We know the sum of n terms

=  $\frac{n(n + 1)}{2}$

Now,

$a= 7, d=6 \:and\:n\:=100$

Hence,

The sum of the given series is:

S $= \frac{100}{2} \times (2 \times 7 + 99 \times 6)$

$= 50 (608)$

$= 30400$

Therefore,

Correct option A) 30,400

#Be Brainly❤️

Answer 2

Q:

Find the sum to 200 terms of the series 2 + 5 + 7 + 6 + 12 + 7 + ....

A) 30,400
B) 30,200
C) 34,600
D) 38,400

Answer:   A) 30,400 

Read Description:

we can treat every two consecutive terms as one.

So, we will have a total of 100 terms of the nature:

(2 + 5) + (7 + 6) + (12 + 7).... => 7, 13, 19,....
 
We know the sum of n terms  n(n+1)/2
 
Now, a= 7, d=6 and n=100

Hence the sum of the given series is 

S= 100/2 x[2 x 7 + 99 x 6]

=> 50[608]

=> 30,400.