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TS EAMCET · Maths · Probability

An executive in a company makes on an average 5 telephone calls per hour at a cost of Rs. 2 per call. The probability that in any hour the cost of the calls exceeds a sum of Rs. 4 is

  1. A 2e4-352e5
  2. B 2e5-372e5
  3. C 1-37e4
  4. D 1-18·5e5
Verified Solution

Answer & Solution

Correct Answer

(B) 2e5-372e5

Step-by-step Solution

Detailed explanation

The number of calls per hour is the random variable with mean 5. The required probability of the call cost that exceeds 42 in an hour ⇒Pr>2=1-Pr≤2 =1-e-5+e-551!+e-5522! =1-e-51+5+252 =1-1e5372 ∴ Pr>2=2e5-372e5