Each of the following numbers has two digits blotted out． Which of the numbers could be the number of hours in x days，where x is an integer（）
A: 25■，■06
B: 50■，■26
C: 56■，■02
D: 62■，■50
E: 65■，■20
A: 25■，■06
B: 50■，■26
C: 56■，■02
D: 62■，■50
E: 65■，■20
举一反三
- The average (arithmetic mean) of five number is 26. After one of the numbers is removed, the average (arithmetic mean) of the remaining numbers is 25. What number has been removed ？（） A: 20 B: 25 C: 26 D: 30 E: 32
- The pages of a report are numbered consecutively from 1 to 10. If the sum of the page numbers up to and including page number z of the report is equal to one more than the sum of the page numbers following page number x, then x=（）. A: 4 B: 5 C: 6 D: 7 E: 8
- If the sum of a set of ten different positive prime numbers is an even number, which of the following prime numbers CANNOT be in the set ？（） A: 2 B: 3 C: 5 D: 7 E: 11
- 智慧职教: How many elements has a standard number system? How many Numbers are there for each element?
- Which of the following descriptions of gray numbers is correct? A: A grey number is a kind of uncertain number which exact value and the range are unknown. B: A grey number is a kind of uncertain number which exact value is unknown but the range of the number is known. C: The value range of the gray number can only be an interval. D: Black and white numbers are not gray numbers.