Question

Ambiga invest MYR 8000 (Malaysian ringgits) in a bank offering interest at a rate of 4.6% per
annum compounded monthly.
a. Calculate the amount of money Ambiga has in the bank after seven year.
Answer to a - (now solve b)
FV=8000(1 + (4.6/12(100))^12 x 7
= 8000(1.004)^84
=8000(1.379)
=11032.28 MYR
b. Calculate how long it will take for her money to double.

Answer 1

Answer:

1 to 10

Step-by-step explanation:

or something missing

Answer 2

Answer:

It will take approximately 15 years for Ambiga to double her money.

Step-by-step explanation:

Given that principal = P = MYR 8000

The rate of interest = R = 4.6%

Let the time in years be n and the final amount be A

We know that A = P (1+$\frac{\frac{R}{12} }{100}$)¹²ⁿ

                           = P (1+$\frac{R }{12*100}$)¹²ⁿ

                           = 8000 (1+$\frac{4.6}{12*100}$)¹²⁽⁷⁾

                           = 8000 (1+$\frac{4.6}{12*100}$)¹²⁽⁷⁾

                           = 8000 (1.003833)⁸⁴

                           = 8000* 1.378997

                           = 11031.976 MYR

(b) Now for part b we need to find the time to double the money.

Using A = P (1+$\frac{\frac{R}{12} }{100}$)¹²ⁿ  when A = 2*P

=> 2P = P (1+$\frac{R }{12*100}$)¹²ⁿ

=> 2 = (1+$\frac{4.6}{12*100}$)¹²ⁿ

=> 2 = (1.003833)¹²ⁿ

We will solve this using log

Thus, taking log both sides, we get,

log 2 = log  (1.003833)¹²ⁿ

=> log 2 = 12n* log  (1.003833)

=> 0.30 = 12n * 1.661 ×10⁻³

=> 12 n = 0.30 / (1.661 ×10⁻³)

=> 12 n = 180.61

=> n = 180.61/12

=> n = 15.05 years

Therefore, it will take approximately 15 years for Ambiga to double her money.