Explanation
$${\textbf{Step -1: Define factor and solve}}$$
$${\text{Any number multiplied by 1 is that number itself, so 1 is the common factor of every number.}}$$
$${\Rightarrow\text{1 is the greater factor of itself and smaller factor of any other number.}}$$
$${\text{As we observe except 1 other numbers are not a factor of every number}}$$
$${\textbf{Hence, 2,3,5 are not a factor of every number}}$$
$${\textbf{Step - 1 : Describe the rules of divisibility test of 3}}{\text{.}}$$
$${\text{As per the rule , any number can divisible by 3 if and only if}}$$
$${\text{ the last sum of the digits of this number is a multiple of 3,itself}}{\text{.}}$$
$${\textbf{Step - 2 : Check with divisibility test for the options}}{\text{. }}$$
$${\text{For option A, The sum of digits of 68 is}}=6+8=14{\text{.}}$$
$${\text{So obviously 14 is not a multiple of 3.So 68 is not divisible by 3.}}$$
$${\text{For option B, The sum of digits of 45 is}}=4+5=9{\text{.}}$$
$${\text{So 9 ist a multiple of 3.So 45 is divisible by 3.}}$$
$${\text{For option C, The sum of digits of 20 is}}=2+0=2{\text{.}}$$
$${\text{So obviously 2 is not a multiple of 3.So 20 is not divisible by 3.}}$$
$${\text{For option D, The sum of digits of 65 is}}=6+5=11{\text{.}}$$
$${\text{So obviously 11 is not a multiple of 3.So 65 is not divisible by 3.}}$$
$${\textbf{Hence, The number which is divisible by 3 is 45(B)}}{\text{.}}$$
Please disable the adBlock and continue. Thank you.
