In a class, 70% student can speak English, 65% can speak Hindi and 27% can speak neither English nor Hindi. If 124 students can speak both languages then find the no. of students who can speak only Hindi. (A) 6 (B) 8 (C) 10 (D) 24
Answers
SOLUTION
TO CHOOSE THE CORRECT OPTION
In a class, 70% student can speak English, 65% can speak Hindi and 27% can speak neither English nor Hindi. If 124 students can speak both languages then the no. of students who can speak only Hindi.
(A) 6
(B) 8
(C) 10
(D) 24
EVALUATION
Let total number of students = 100x
Let
E : The set of students who can speak English
H : The set of students who can speak Hindi
By the given condition
n(E) = 70x , n(H) = 65x
Now 27% can speak neither English nor Hindi
So ( 100 - 27) % = 73% can speak atleast one of English or Hindi
n(E ∪ H) = 73x
Now
n(E ∪ H) = n(E) + n(H) - n(E ∩ H)
⇒ 73x = 70x + 65x - n(E ∩ H)
⇒ n(E ∩ H) = 135x - 73x
⇒ n(E ∩ H) = 62x
By the given condition
62x = 124
⇒ x = 2
The number of students who can speak only Hindi
= E(H) - n(E ∩ H)
= 65x - 62x
= 3x
= 3 × 2
= 6
FINAL ANSWER
Hence the correct option is (A) 6
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From the given question the correct option is (A) 6.
Solution :
Let total number of students = 100x
Let
E : The set of students who can speak English
H : The set of students who can speak Hindi
By the given condition
n(E) = 70x , n(H) = 65x
Now 27% can speak neither English nor Hindi
So ( 100 - 27) % = 73% can speak atleast one of English or Hindi
n(E ∪ H) = 73x
Now
n(E ∪ H) = n(E) + n(H) - n(E ∩ H)
⇒ 73x = 70x + 65x - n(E ∩ H)
⇒ n(E ∩ H) = 135x - 73x
⇒ n(E ∩ H) = 62x
By the given condition
62x = 124
⇒ x = 2
The number of students who can speak only Hindi
= E(H) - n(E ∩ H)
= 65x - 62x
= 3x
= 3 × 2
= 6
FINAL ANSWER
Hence the correct option is (A) 6