Question

A person deposited Rs. 1000 in a bank at 5% compounded annually. After 5years, the rate of interest was
increased to 6% and after 4 more years, the rate was further increased to 7%. The money was withdrawn
at the end of 12 yrs. Find the amount.​

Answer 1

He will received the amount 1973.88 after 12 years.

Step-by-step explanation:

A person deposited 1000 Rs. in a bank.

He got rate of interest for first 5 years 5%.

$A=P(1+\frac{r}{n})^{nt}$

A = future amount

P = Principal amount = 1000 Rs.

r = Rate of interest = 5% = 0.05

n = number of compounding = 1

t = time = 5 years

$A=1000(1+(\frac{0.05}{1} )^{(1\times5)}$

   $=1000(1+0.05)^5$

   = 1000 × (1.05)⁵

   = 1000 × 1.276281

   = 1276.28 Rs.

Now principal amount would be = 1276.28 Rs.

r = 6% = 0.06

t = 4 years

$A=1276.28(1+\frac{0.06}{1})^4$

   =  $1276.28(1+0.06)^4$

   = 1276.28 × 1.26247

   = 1611.27 Rs.

The money was withdrawn at the end of 12 years.

The remaining years of deposit = 12 -(5+4) = 3 years

Now principal amount would be = 1611.27 Rs.

r = 7% = 0.07

t = 3 years

$A=1611.27(1+\frac{0.07}{1})^{(1\times3)}$

   $=1611.27(1+0.07)^3$

   = 1611.27 × 1.2250

   = 1973.8750 ≈ 1973.88 Rs.

He will received 1973.88 Rs. at the end of 12 years.

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