Answer:
27
Step-by-step explanation:
To find the number of students who read booth biology and chemistry, we say
let B rep student that study Biology and C for Chemistry
B = 19, C = 16
So, student that study only Biology (B n C') = 19 - x
Chemistry (B' n C) = 16 - x
Total n(u) = n(B n C') + n(B n C) + n(B' n C) + n(B n E)'
36 = (19-x) + (x) + (16-x) + 5
36 = 19-x +x +16-x + 5
36 = 19 + 16 + 5 - x
36 = 40 -x, x = 40 - 36
x = 4
we use the value of x to calculate to find question b.
student that study biology only = 19 -4 = 15
chemistry only = 16 -4 = 12
>>> students that study both subject equals 12 + 15 = 27.
