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12 votes
12 votes
A $10,000 investment earned interest at 4.5%

compounded quarterly for 1 year and 5.5% compounded quarterly for the next year. What is the amount in the account at the end of 2 years?

User Tmporaries
by
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1 Answer

21 votes
21 votes

Answer: $11,044.79

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Step-by-step explanation:

We use this formula for compound interest

A = P*(1 + r/n)^(n*t)

The variables are,

  • A = final amount after t years
  • P = initial deposit aka principal
  • r = annual interest rate in decimal form
  • n = number of times we compound the money
  • t = number of years

For the first year, we have this set of values

  • P = 10,000
  • r = 0.045
  • n = 4
  • t = 1

Which leads to this

A = P*(1 + r/n)^(n*t)

A = 10,000*(1 + 0.045/4)^(4*1)

A = 10,457.6508633057 approximately

A = 10,457.65 after rounding to the nearest cent

This value of A will be the new deposit value P when we do another round of calculations. For the second round, we have

  • P = 10,457.65
  • r = 0.055
  • n = 4
  • t = 1

So,

A = P*(1 + r/n)^(n*t)

A = 10,457.65*(1 + 0.055/4)^(4*1)

A = 11,044.7927637434

A = 11,044.79

There is $11,044.79 in the account after 2 years.

For each case, the value of n = 4 stays the same (since both rounds are compounding quarterly, aka 4 times a year). Also, we have t = 1 the same because each timespan is 1 full year.

Side note: The total amount of interest earned is 11,044.79 - 10,000 = 1,044.79 dollars.

User Rahul Goswami
by
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