1.

In a group of 950 persons, 750 can speak Hindi and 460 can speak English. Find:(i) How many can speak both Hindi and English.(ii) How many can speak Hindi only.(iii) how many can speak English only.

Answer»

Here, we have,

Suppose, the total number of people be n (P) = 950

The people who can speak English n (E) = 460

The people who can speak Hindi n (H) = 750

(i) How many people can speak both Hindi and English.

The people who can speak both Hindi and English = n (H ∩ E)

As we know,

n (P) = n (E) + n (H) – n (H ∩ E)

By substituting the values we get

950 = 460 + 750 – n (H ∩ E)

950 = 1210 – n (H ∩ E)

n (H ∩ E) = 260

∴ Number of people who can speak both English and Hindi are 260.

(ii) How many people can speak Hindi only.

As we can see that H is disjoint union of n (H–E) and n (H ∩ E).

(If A and B are disjoint then n (A ∪ B) = n (A) + n (B))

∴ H = n (H–E) ∪ n (H ∩ E)

n (H) = n (H–E) + n (H ∩ E)

750 = n (H – E) + 260

 n (H–E) = 490

∴ 490 people can speak only Hindi.

(iii) How many people can speak English only.

As we can see that E is disjoint union of n (E–H) and n (H ∩ E)

(If A and B are disjoint then n (A ∪ B) = n (A) + n (B))

∴ E = n (E–H) ∪ n (H ∩ E).

n (E) = n (E–H) + n (H ∩ E).

460 = n (H – E) + 260

n (H–E) = 460 – 260 = 200

Hence, 200 people can speak only English.



Discussion

No Comment Found

Related InterviewSolutions