Harikishore said – Wed, 01 Jul 2009 07:27:45 -0000 ( Link )
Find the number of numbers less than 2000 that can be formed by using the digits 1,2,3,4 if repetition is allowed
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indianschoolofbusiness said – Thu, 02 Jul 2009 05:30:19 -0000 ( Link )
The answer is 4^3. Since the first place can have only 1 and the rest of the places viz., 2nd,3rd and 4th places can still have 1,2,3 &4. Therefore 4 * 4 * 4.
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Sureshbala said – Sat, 04 Jul 2009 13:48:23 -0000 ( Link )
Number of single digit numbers = 4.
Number of two digit numbers = 4×4 = 16
Number of three digit numbers = 4×4 x 4 = 64
Number of four digit numbers
The first digit can be only 1 and the rest three digits could be any one of the given four digits. Hence the number of four digits numbers = 4×4 x 4 = 64
Thus, the total number of numbers that can be formed is 148
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Harikishore said – Mon, 06 Jul 2009 06:12:22 -0000 ( Link )
Thanks Suresh Bala for a comprehensive answer. The trick here is to identify that there can be single, two and three digit numbers apart from 4 didgit numers that can be formed using 1,2,3,4. The correct answer is 148.
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Sureshbala said – Mon, 06 Jul 2009 07:29:13 -0000 ( Link )
Yes, most of us give the answer as 64 just considering the 4 digit numbers. Very good questions to test your vigilance
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hamzu said – Sat, 04 Jul 2009 12:52:55 -0000 ( Flag Edit Link )
the last no would be 1999, hence we can fill first place with only 1 n rest with any 4 no.,,,hence answer wud b 14*44=64