i tried working this and am getting negative answers and i doubt my answers because it not possible to get negative number of people. PLEASE HELP ME
QUESTION
A college doctor found out that 40 students have had food poisoning. He found out the following after interviewing them.
25, 27 and 30 took rice, beans and plantain respectively.
28 took rice or plantain but not beans
13 took rice and plantain
10 took rice but did not take beans and plantain
7 took beans and plantain but not rice
determine the number of students who
a. took none of the meal
b. took all the three meal
c. took only one meal
d. took more than one meal