CAT 2020 Quant Question [Slot 3] with Solution 16

Question

How many integers in the set {100, 101, 102, ..., 999} have at least one digit repeated?

Option: 252
Solution:

The given set is a set of all three-digit numbers and the number of numbers in the set =900.

The number of three-digit numbers having no digits repeating \( = 9 \times 9 \times 8 = 648\)

Required answer =900-648=252

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CAT 2020 Quant questions with Solutions