A man deposited ₹10000 in a bank at the rate of 5% simple interest annually. Find the amount in the 15^th year since he deposited the amount and also calculate the total amount after 20 years

Solution:

It is given that the man deposited ₹10000 in a bank at the rate of 5% simple interest annually.

Hence, annual interest received in ₹ = 5/100 x 10000 = 500

Amount in ₹ at the end of first year = 10000 + 500 = 10500

Amount in ₹ at the end of second year = 10500 + 500 = 11000

Amount in ₹ at the end of third year = 11000 + 500 = 11500

Therefore, 10000, 10500, 11000, .... is an A.P.

Hence, the amount in the 15^th year using the nᵗʰ term of A.P. formula,

a₁₅ = 10000 + (15 - 1)(500)

= 10000 + 7000

= 17000

Amount after 20 years

a₂₁ = 10000 + (21 - 1)(500)

= 10000 + 10000

= 20000

Thus, the amount in 15^th year is ₹17000 and after 20 years amount is ₹ 20000

NCERT Solutions Class 11 Maths Chapter 9 Exercise ME Question 30