Given:

People who speak Hindi = 50

People who speak English = 20

People who speak both English and Hindi = 10

To Find: People who speak at least one of these two languages

Let us consider,

People who speak Hindi = n(H) = 50

People who speak English = n(E) = 20

People who speak both Hindi and English = n(H ∩ E) = 10

People who speak at least one of the two languages = n(H ∪ E)

Venn diagram:

Now, we know that,

n(A ∪ B) = n(A) + n(B) – n(A ∩ B)

Therefore,

n(H ∪ E) = n(H) + n(E) – n(H ∩ E)

= 50 + 20 – 10

= 60

Thus, People who speak at least one of the two languages are 60.