Question

(1) In a district co-operative bank, Mr. Surendra invested Rs. 500 in 2001,
Rs. 1500 in 2002, Rs. 2500 in 2003. If he keeps on investing in the
bank upto 2020 in the same manner, how much investment will there
be in his account at the end of 2020 ?


ANSWER
​

Answer 1

Answer:

2,00,000

Step-by-step explanation:

this terms are like AP : 500 , 1500 , 2500,...

d = 1500-500 = 1000

n = 20

$an = a + (n - 1)d \\ a20 = 500 + (20 - 1)1000 \\ = 500 + 19(1000) \\ = 500 + 19000 \\ a20 = 19500$

$s20 = n \div 2(a + l) \\ = 20 \div 2(500 + 19500) \\ = 10 \times 20000 \\ = 200000$

hence, the total investment of MR.surendra is 2,00,000

Answer 2

Answer:

Her investment till 2020 is ₹19,500

Step-by-step explanation:

In

2001= ₹ 500

2002=₹1500

2003=₹2500

2004=₹3500

2005=₹4500

2006 =₹5500

2007 =₹ 6500

2008= ₹7500

2009=₹8500

2010=₹9500

2011=₹10500

2012=₹11500

2013=₹12500

2014=₹13500

2015=₹14500

2016=₹15500

2017 =₹16500

2018 =₹17500

2019 =₹18500

2020=₹19500