Question

Express $B=\{x|x$ is two-digit number such that the product of its digits is a multiple of ten$\}$ in the roster form.

• A. $B=\{10,20,30,40,50,60,70,80\}$
• B. $B=\{25,45,53,54,57,58,55,95\}$
• C. $B=\{25,45,52,54,56,58,65,85\}$
• D. Data insufficient
  

Answer 1

The correct option is C $B=\{25,45,52,54,56,58,65,85\}$

The product of digits of the two-digit numbers will be multiple of $10$ if one digit is $5$ and the other one is even number.
These number are $25,45,52,54,56,58,65,85.$
$\therefore B=\{25,45,52,54,56,58,65,85\}$