

InterviewSolution
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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. |
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