ANSWER
20 %
Step-by-step explanation
Let's say B's salary is 100. Given that A's salary is 25% higher than B's salary, then A's salary would be,
To find how many percents is B's salary less than A's, we have to divide the portion of B's salary that is higher than A's, which is 25, by A's salary. And then multiply by 100% to obtain it as a percentage,
Therefore, B's salary is 20% less than A's.