Question

Sachin invested rs 5000 for the 1st year ,7000 for the 2nd year ,9000 in the 3rd year in

National Saving Certificate scheme .How much amount did he invest in 12 years?​

Answer 1

Answer:Answer:

192000

Step-by-step explanation:

Sachin invested in first year = 5000

He invested in second year = 7000

he invested in third year = 9000

And so on

So, sequence becomes : 5000,7000,9000,......

So, a = first term = 5000

d = common difference = 7000-5000=9000-7000 =2000

Now we are supposed to find find the total amount that he invested in 12 years

So, Formula of sum of n terms in AP = \frac{n}{2} (2a+(n-1)d)

Now substitute n =12

So total amount he invested in 12 years :

= \frac{12}{2} (2(5000)+(12-1)2000)

= 192000

Thus the total amount that he invested in 12 years is 192000

Step-by-step explanation: