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Re: How many two-digit numbers can be formed from the digits 1 t
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01 Aug 2020, 04:10
we asked to form 2-digit number containing numbers from 1-9 without repetition. First digit will have any number from 1 to 9, can be formed in 9 way second digit can be formed in 8 ways. therefore, total ways to form that number = 9*8=72 answer is B
Re: How many two-digit numbers can be formed from the digits 1 t
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03 Aug 2020, 03:59
1
Experiment: Find all the possible two digit numbers that only use digits 1-9 and no digit repeats. Event1: choose a digit for your tens place Event2: choose a digit for your ones place
Number of possible outcomes for Event1: 9 Namely: 1,2,3,4,5,6,7,8,9
Number of possible of outcomes for Event2: 8 Namely: we can choose any number from 1 to 9 except the one chosen in Event1
By Fundamental Counting Principle: # of outcomes in the entire experiment is the product of the number of possible outcomes in both events. 9*8=72
But why can we use Fundamental Counting Principle? B/C no matter what number we choose in Event1 we'll always have 8 possible outcomes in Event2. That is, the NUMBER of possible outcomes of each event is independent of one another. If the number of possible outcomes between both events was not independent then we wouldn't be able to use Fundamental Counting Principle.
Re: How many two-digit numbers can be formed from the digits 1 t
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07 Jul 2024, 18:09
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Re: How many two-digit numbers can be formed from the digits 1 t [#permalink]