A number is drawn at random from the numbers 1 through 20.The probabilty the number is a multiple of 3 is

Answer 1

Multiples of 3 below 20 are = { 3 , 6 , 9 , 12 , 15 , 18 }

Number of favorable events are p(f) =  6 .

A number is drawn at random from 1 through 20 .

Total number of possible events are p(t) = 20 .

Probability of favorable events is = (Number of favorable events)/(Total number of events)⇒p(f)/p(t)

The probability the number is a multiple of 3 is = p(f) / p(t) 

                                                             = 6/20 =0.3

Therefore the probability the number is a multiple of 3 is 0.3 .