CAT Quantitative Ability Questions | CAT Permutation, Combination and Probability questions
CAT/2002
Question . 39
How many numbers greater than 0 and less than a million can be formed with the digits of 0, 7 and 8?
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Explanatory Answer
Method of solving this CAT Quantitative Ability Question from Permutation, Combination and Probability question
(c) No. of 1 digit numbers = 2No. of 2 digit numbers = 3 × 2 = 6
No. of 3 digit numbers = 3 × 3 × 2 =18
No. of 4 digit numbers = 33 × 2 = 54
No. of 5 digit numbers = 34 × 2 = 162
No. of 6 digit numbers (less than a million) = 35 × 2 = 486
∴ Required numbers = 486 + 162 + 54 + 18 + 6 + 2 = 728