1.

Three integers are chosen at random from the first 20 integers. The probability that their product is even is A. \(\frac{2}{19}\)B. \(\frac{2}{29}\)C. \(\frac{17}{19}\)D. \(\frac{4}{19}\)

Answer»

3 integers out of 20 can be chosen in 20C3 ways. 

As in first 20 integers, 10 are even. 

To have the product of 3 integer even the chosen integers must be even.

∴ 3 integers that are even can be chosen from first 20 integers in 10C3 ways. 

∴ Probability =  \(\frac{^{10}C_2}{^{20}C_2}\) = \(\frac{10\times9\times8}{20\times19\times18} = \frac{2}{19}\) 

Our answer matches with option (a) 

∴ Option (a) is the only correct choice



Discussion

No Comment Found

Related InterviewSolutions