Explanation:

Correct option 3: 30

Given:

• Total people = 150

• Tea (T) = 75

• Coffee (C) = 60

• Milk (M) = 50

• Tea ∩ Coffee = 15

• No one taking milk takes tea ⇒ T ∩ M = 0

• Everyone takes at least one drink

• Need to find: Milk only

Step-by-step (Quick Method):

1. Only Tea = 75 − 15 = 60

2. Only Coffee = 60 − 15 = 45

3. Let x = number of people who take both Milk and Coffee

Then:
Total = Only Tea + Only Coffee (excluding Milk) + Tea & Coffee + Only Milk + Milk & Coffee

150=60+(45−x)+15+(50−x)+x⇒150=170−x⇒x=20

4. So, Only Milk = 50 − x = 50 − 20 = 30