Plz fast will give !

an education company conducted four separate surveys of students in a city about the subject they found most difficult. each survey randomly selected 100 students in the city. the results are shown in the table.

survey math english science history total
#1 31 25 24 20 100
#2 29 25 25 21 100
#3 30 24 23 23 100
#4 15 50 15 20 100
identify surveys that are likely biased.

based on the unbiased surveys, what percent of the students in the city would say that science is the subject they find most difficult?