Question

Of 100 students surveyed, 95 like milk or juice, 30 like both milk and juice, and 45 like juice. How many students like milk?

Answer 1

Looks like 5 don't like neither milk nor juice, a fact which does not enter the picture.

Number(M or J) = number(M) + number(J) - number(M and J)
95 = number(M) + 45 - 30

continue ....