Question

sachin invested some amounts in national saving certificates in a specific way In the first year he invested ₹4000 in the second year ₹6000 in the third year ₹8000 and so on for 12 year find the total amount he invested in 12 year​

Answer 1

Answer:

180000

Step-by-step explanation:

This question is based on AP(arithmetic progression)

At first you have to find out 12th year invested amount,

hence , You know that if $T_{12$ = 1st investment + (n-1) difference

= 4000+ (12-1)2000

= 4000+22000

= 26000

Now Sum of all investment in 12 year=  n/2(1st investment+last investment)

= 12/2(4000+26000)

=  6*30000

= 180000 Rs ans.