To determine which option is both a real number and an integer, let’s analyze each choice:
- a) 23: This is a whole number, and it fits the definition of both a real number and an integer.
- b) 1 4: This appears to be a formatting error, as it doesn’t represent a recognizable number.
- c) √27: The square root of 27 is approximately 5.196. While it is a real number, it is not an integer because it is not a whole number.
- d) 3 402538: Similar to option b, this seems to be a formatting issue or a typo and does not represent a valid number.
Thus, the only choice that is both a real number and an integer is a) 23.