If I = {x : x is a two-digit natural number and both its digits are equal}, what is I?
Answer and explanation
Correct answer: I = {11, 22, 33, 44, 55, 66, 77, 88, 99}
A two-digit natural number has a nonzero tens digit. If both digits are equal, the repeated digit can be 1 through 9, producing 11, 22, 33, 44, 55, 66, 77, 88, and 99. The form 00 is not a two-digit natural number because its tens digit is zero. Option C contains unequal digits, while D contains one-digit numbers. Therefore A is correct.
Frequently asked questions
What is the correct answer to this question?
I = {11, 22, 33, 44, 55, 66, 77, 88, 99}
Why is this the correct answer?
A two-digit natural number has a nonzero tens digit. If both digits are equal, the repeated digit can be 1 through 9, producing 11, 22, 33, 44, 55, 66, 77, 88, and 99. The form 00 is not a two-digit natural number because its tens digit is zero. Option C contains unequal digits, while D contains one-digit numbers. Therefore A is correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Sets and their representations.
