It's the sum of the three masses:

Answer:
d
Step-by-step explanation:
The answer is B part
As the requirement for the student is either a senior or one who studies maths or both.
So, just add the values within the two venn circles divide it by total no of values.
=> 240+40+110/240+40+110+840
=> 360/1200
Answer:
450
Step-by-step explanation:
The answer is the fraction 12/16 is also part of the pattern