Olympiad workbookIOQMSequences and Series

Five distinct 2-digit numbers are in a geometric progression. Find the middle term.

Correct answer

Step-by-step solution

Let the numbers be a ar a r^2 a r^3 a r^4 since all are 2 digit number r= 2 3 or 3 2 (as fourth power of integers greater than 3 are 3 digit numbers) Hence the five numbers are (16,24,36,54,81) Hence middle term is 36 .

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