Q. |
How many numbers not exceeding 7654 can be formed from the digits 4, 5, 6, and 7? |
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A. 313 |
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B. 229 |
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C. 192 |
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D. 193 |
From the digits 4, 5, 6, and 7 means repetition is allowed.
One digit number: 4
Two-digit numbers: 4 × 4 =16
Three-digit numbers: 4 × 4 × 4 = 64
Four-digit numbers: beginning with 4: 4 × 4 × 4 = 64
Four-digit numbers: beginning with 5: 4 × 4 × 4 = 64
Four-digit numbers: beginning with 6: 4 × 4 × 4 = 64
Four-digit numbers: beginning with 74: 4 × 4 = 16
Four-digit numbers: beginning with 75: 4 × 4 = 16
Four-digit numbers: beginning with 764: = 4
Four-digit numbers: beginning with 765: = 1 i.e= (7654)
Total numbers = 4+16+64+64+64+64+16+16+1 = 313