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A salesman is known to sell a product in 3 out of 5 attempts. While another salesmas in 2 out of 5 attempts. Could you please help me find the probability that
1) no sales will happen
2)either of them will succeed in selling the product

Lets say salesman A is successful in 3 out of 5 times, then his probability of success is P(A) = 3/5 = 0.6. Similarly, salesman B has P(B) = 0.4. On the other hand, the probability that they are not successful, for each individually, is P(A|none) = 1 - P(A) = 0.4 and P(B|none) = 1 - P(B) = 0.6.

a) The probability that both will be unsuccessful is

P(A and B|none) = P(A|none)・P(B|none) = P(A nor B) = (0.4)・(0.6) = 0.24.

b) The probability that one or the other is successful can be calculated 2 ways

1. 1 - probability neither is successful = 1 - P(A nor B) = 1 - 0.24 = 0.76

2. Probability of P(A) or P(B)  = P(A) + P(B) - P(A nor B) = 0.6 +0.4 - 0.24 = 0.76.

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randy patton


college mathematics, applied math, advanced calculus, complex analysis, linear and abstract algebra, probability theory, signal processing, undergraduate physics, physical oceanography


26 years as a professional scientist conducting academic quality research on mostly classified projects involving math/physics modeling and simulation, data analysis and signal processing, instrument development; often ocean related

J. Physical Oceanography, 1984 "A Numerical Model for Low-Frequency Equatorial Dynamics", with M. Cane

M.S. MIT Physical Oceanography, B.S. UC Berkeley Applied Math

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