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JEE Main 202331 JanuaryMorning Shift
Exam
JEE Main
Year
2023
Date
31 January
Shift
Morning Shift
Subject
Mathematics
Chapter
Permutation and Combination

JEE Main 2023 · 31 January · Morning Shift · Mathematics · Permutation and Combination

Let 5 digit numbers be constructed using the digits 0, 2, 3, 4, 7,...

Let 55 digit numbers be constructed using the digits 0,2,3,4,7,90, 2, 3, 4, 7, 9 with repetition allowed, and are arranged in ascending order with serial numbers. Then the serial number of the number 4292342923 is _____ .

Correct answer

0

Step-by-step solution

Number of five-digit numbers formed using the digits 0,2,3,4,7,90, 2, 3, 4, 7, 9 with 22 at the first place is

=6×6×6×6=1296= 6 \times 6 \times 6 \times 6 = 1296

Since, 2+6+6+6+6=12962\mathop{+}_{6}\mathop{+}_{6}\mathop{+}_{6}\mathop{+}_{6} = 1296

Number of five-digit numbers formed using the given digits with 33 at the first place is

=1296= 1296

Since, 3+6+6+6+6=12963\mathop{+}_{6}\mathop{+}_{6}\mathop{+}_{6}\mathop{+}_{6} = 1296

Number of five-digit numbers formed using the given digits with 4040 at the first place is

=216= 216

Since, 40+6+6+6=21640\mathop{+}_{6}\mathop{+}_{6}\mathop{+}_{6} = 216

And,

420+6+6=36420\mathop{+}_{6}\mathop{+}_{6} = 36

422+6+6=364 2 2 \mathop{+}_{6}\mathop{+}_{6} = 36

423+6+6=36423\mathop{+}_{6}\mathop{+}_{6} = 36

424+6+6=36424\mathop{+}_{6}\mathop{+}_{6} = 36

427+6+6=36427\mathop{+}_{6}\mathop{+}_{6} = 36

4290+6=6429 0 \mathop{+}_{6} = 6

42920=142920 = 1

42922=142922 = 1

42923=142923 = 1

Required serial number is

=1296×2+216+5×36+6+1+1+1=2997= 1296 \times 2 + 216 + 5 \times 36 + 6 + 1 + 1 + 1 = 2997

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