Question

100 students are interviewed to see which of biology, chemistry or physics they prefer.

39 of the students are girls. 21 of the girls like biology best.
16 of the boys prefer physics.
11 out of the 34 who prefer chemistry are girls.
What percentage of the students prefer biology?

Answer 1

43% of the students prefer biology

Explanation:

Among girls:

39 of the students are girls.

21 of the girls like biology best.

Boys:

100 - 39 = 61 are boys.

16 prefer physics

11 out of the 34 who prefer chemistry are girls, so 34 - 11 = 23 are boys.

61 - (16 + 23) = 22 prefer biology.

What percentage of the students prefer biology?

21 boys and 22 boys, that is, 43 students out of 100. So

43*100%/100 = 43%

43% of the students prefer biology