GMAT Focus EditionQuantitative ReasoningMedium

A financial manager is comparing two investment options. Option 1 offers an 8% annual interest rate compounded quarterly. Option 2 offers a 7.8% annual interest rate compounded monthly. Which option offers a higher effective annual interest rate (EAR)?

  1. AOption 2, with an EAR of approximately 8.12%
  2. BOption 1, with an EAR of approximately 8.24%
  3. COption 2, with an EAR of approximately 8.08%
  4. DOption 1, with an EAR of approximately 8.16%
Show answer & explanation

Correct answer: B. Option 1, with an EAR of approximately 8.24%

To compare, we must calculate the Effective Annual Interest Rate (EAR) for both options using the formula EAR = (1 + r/n)^n - 1, where r is the nominal annual rate and n is the number of compounding periods per year. For Option 1: r = 0.08, n = 4 (quarterly). EAR = (1 + 0.08/4)^4 - 1 = (1 + 0.02)^4 - 1 = (1.02)^4 - 1 ≈ 1.082432 - 1 ≈ 0.082432 or 8.24%. For Option 2: r = 0.078, n = 12 (monthly). EAR = (1 + 0.078/12)^12 - 1 = (1 + 0.0065)^12 - 1 ≈ 1.080849 - 1 ≈ 0.080849 or 8.08%. Comparing the two, Option 1 (8.24%) offers a higher EAR than Option 2 (8.08%).

Why the other options are wrong

  • A. This is a plausible distractor, perhaps from a calculation error for Option 2 or incorrect comparison.
  • C. This correctly calculates EAR for Option 2 but incorrectly states it's higher.
  • D. This is a plausible distractor, perhaps from a calculation error for Option 1.

Effective Annual Interest Rate (EAR)

The Effective Annual Interest Rate (EAR) is the actual annual rate of return earned on an investment or paid on a loan, taking into account the effect of compounding over a year. It allows for a standardized comparison of different interest rates with varying compounding periods.

  • Formula: EAR = (1 + r/n)^n - 1, where r is the nominal rate and n is compounding periods per year.
  • Higher compounding frequency (larger 'n') generally leads to a higher EAR for a given nominal rate 'r'.
  • EAR is always greater than or equal to the nominal rate for positive interest rates.

Memory trick: EAR: Rate 'r' divided by 'n', raised to 'n', then minus one for the true gain.

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