Of 1000 surveyed students, 20% of those who read book A also read book B and 25% of those who read book B also read book A. If each student read at least one of the books, what is the difference between the number of students who read only book A and the number of students who read only book B?	Choose the correct choice from the following answers.
A) 120  B) 125  C) 130  D) 145  E) 155
Say the number of students who read book A is A and the number of students who read book B is B.   Given that 20% of those who read book A also read book B and 25% of those who read book B also read book A, so the number of students who read both books is 0.2A=0.25B --&gt; A=1.25B.   Since each student read at least one of the books then {total}={A}+{B}-{Both} --&gt; 1000=1.25B+B-0.25B --&gt; B=500, A=1.25B=625 and {Both}=0.25B=125.   The number of students who read only book A is {A}-{Both}=625-125= 
<gadget id="calculator">625-125</gadget>
<output>500</output>
500;   The number of students who read only book B is {B}-{Both}=500-125= 
<gadget id="calculator">500-125</gadget>
<output>375</output>
375   The difference is 500-375= 
<gadget id="calculator">500-375</gadget>
<output>125</output>
125.   Answer: 125.
<result>B</result>
Of 1000 surveyed students, 20% of those who read book A also read book B and 25% of those who read book B also read book A. If each student read at least one of the books, what is the difference between the number of students who read only book A and the number of students who read only book B?