Question

three distinct integers are chosen at random from first 20 positive integers.compute the probability that their product is even

Answer 1

Answer:

~ 0.89

Step-by-step explanation:

total numbers : 20

odds = 10 & evens = 10

all three numbers products = 20C3

but we know that.....

odd × odd × even = even

even × odd × even = even

even × even × even = even

odd × odd × odd = odd

hence.....

all combinations of 3 numbers in 20 numbers except three odds together

i.e, 20C3 - 10C3

= 1140 - 120 = 1020

therefore...

P(even) = 1020 / 1140 = 17/19 ~ 0.89