How do u solve this?
1 answer:
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Answer:
87.9
Step-by-step explanation:
Use a calculator or table to find the z-score that corresponds to 25%.
P(Z < z) = 0.25
z = -0.675
Now find the value that corresponds to that z score.
z = (x − μ) / σ
-0.675 = (x − 101.3) / 19.9
x = 87.9
➻ In a group of 40 people, 27 can speak English and 25 can speak Spanish.
➻ The required number of people who can speak both English and Spanish .
<u>Consider</u> ,
➻ A → Set of people who speak English.
➻ B → Set of people who speak Spanish
➻ A∩B → Set of people who can speak both English and Spanish
- ➻ n (A) = 27
- ➻ n (B) = 25
- ➻ n (A∪B) = 40
- ➻ n(A∩B) = ?
➻ n(A∪B) = n(A) + n (B) - n(A∩B)
➻ 40 = 27 + 25 - n (A∩B)
➻ 40 = 52 - n (A∩B)
➻ n (A∩B) = 52 - 40
➻ ∴ n (A∩B) = 12
∴ Required Number of persons who can speak both English and Spanish are <u>12 .</u>
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➻ n(A∪B) = n(A) + n (B) - n(A∩B)
➻ 40 = 27 + 25 - 12
➻ 40 = 52 - 12
➻ 40 = 40
➻ ∴ L.H.S = R.H.S
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