6,240 is divisible by

a. 3

b. 9

c. 8

Explain your reasoning for your choice (s).

a. 3 & c. 8

The given number is divisible by both 3 & 8.

Step-by-step explanation:

Divisibility rule for 8 : A number is divisible by 8 if the last two digits of that number are divisible by 8 i. e. the numbers at the tenth and ones place of the given number appear in the table of 8.

The given number i. e. 6,240 has 40 in the tenth and ones place and we all know that 40 is completely divisible by 8 (40/8 = 5) so option c is the right answer for this question.

6,240 / 8 = 780.

Divisibility rule for 3: If the sum of all the digits of a given number is completely divisible by 3 then the number is said to be divisible by 3.

In the given question, the sum of all the digits of the given number is as under:

6,240 = 6 + 2 + 4 + 0 = 12.

We all know that 12 is completely divisible by 3 (12/3 = 4) so option a is also correct.

6,240/3 = 2,080.

Divisibility rule for 9: If the sum of all the digits of a given number is completely divisible by 9 then the number is said to be divisible by 9. As already explained the sum total of the given number is 12 which is not completely divisible by 9. So, this option is incorrect.

6,240/9 = 693.33 i. e. it is not completely divisible by 9.