The 9. In a ceremony, out of 800 participants, 620 drank milk, 350 drank tea and 50 did not
drink any of them. Find out how many people drank the both drinks using a Venn
diagram?​

220

Explanation:

Let M represent the amount of people that drank milk, let T represent the people that drank tea.

Let x represent the people that drank both milk and tea.

Therefore. the amount of people that drank only milk = n(M ∩ T') = 620 - x

the amount of people that drank only milk = n(M' ∩ T) = 350 - x

The amount of people that did not drink any of them = n(M ∪ T)'

Since 800 people participated, Hence:

620 - x + (350 - x) + x + 50 = 800

620 + 350 + 50 - x - x + x = 800

1020 - x = 800

x = 1020 - 800

x = 220

Therefore 220 people drank both drinks.