Which option is the roster form of I = {x ∈ N : 50 < x < 70 and x is divisible by 5}?
Answer and explanation
Correct answer: I = {55, 60, 65}
The inequalities are strict, so neither 50 nor 70 can be included. The multiples of 5 between these endpoints are 55, 60, and 65. Each is a natural number and is divisible by 5, so all three satisfy the definition. Therefore, the roster form is I = {55, 60, 65}, which is option A. The other options incorrectly include one or both boundary values.
Frequently asked questions
What is the correct answer to this question?
I = {55, 60, 65}
Why is this the correct answer?
The inequalities are strict, so neither 50 nor 70 can be included. The multiples of 5 between these endpoints are 55, 60, and 65. Each is a natural number and is divisible by 5, so all three satisfy the definition. Therefore, the roster form is I = {55, 60, 65}, which is option A. The other options incorrectly include one or both boundary values.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Sets and their representations.
