Question

ram has a recurring deposit account in a bank and pays 400 per month at 10% pa if he gets 16620 at the time of maturity. Find the time for which the account was held​

Answer 1

Given,

Principal (P) = Rs. 400

Rate of Interest (R) = 10 % p.a.

Maturity Value (M.V) = Rs. 16620

M.V = (P*n)+S.I

... where 'n' is the time in months,

= 16620 = (400n)+S.I

= 16620-400n = S.I      .... (i)

S.I = [P*n(n+1)/24*R/100]

Putting equation (i) in place of S.I, we get,

= 16620-400n = [400*(n²+n)/24*10/100]

= 16620-400n = [400*(n²+n)/24*0.1]

= 16620-400n = [50*(n²+n)/3*0.1]

= 16620-400n = (50*0.1*(n²+n))/3

= 49860-1200n = 5n²+5n

= 49860 = 5n²+1205n

= 0 = 5n²+1205n-49860

= 0 = n²+241n-9972

= 0 = n²-36n+277n-9972

= 0 = n(n-36)+277(n-36)

= 0 = (n+277)(n-36)

Value of n can be: -277 or, +36,

As Time cannot be in negative,

The Value of n is 36.

Time is 36 months i.e. 3 years.

I hope this helps.

Answer 2

Answer:

hope it helps to you ,.,.,.,.