Question:
Given an example of a number which is divisible by
(i) 2 but not by 4.
(ii) 3 but not by 6.
(iii) 4 but not by 8.
(iv) both 4 and 8 but not by 32.
Solution:
(i) 10
Every number with the structure (4n + 2) is an example of a number that is divisible by 2 but not by 4.
(ii) 15
Every number with the structure (6n + 3) is an example of a number that is divisible by 3 but not by 6.
(iii) 28
Every number with the structure (8n + 4) is an example of a number that is divisible by 4 but not by 8.
(iv) 8
Every number with the structure (32n + 8), (32n + 16) or (32n + 24) is an example of a number that is divisible by 4 and 8 but not by 32.