Answer:
42%
first we find the totals of each gender which was indicated that there are 29 girls in total ...making it 71 boys there to make100 students .
then it is shown that 9 girls like biology and boys ...anon
20 boys prefer physics and out of the 29 students who like chemistry ..18 are boys which now gives us 38 boys out of 71 .
to get the boys who like biology u subtract 38 from their total which is 71 to get 33.
33 + 9 = 42
42/100 = 42%
