Question

Keith’s Florists has 17 delivery trucks, used mainly to deliver flowers and flower arrangements in the Greenville, South Carolina, area. Of these 17 trucks, 6 have brake problems. A sample of 4 trucks is randomly selected. What is the probability that 2 of those tested have defective brakes? (Round your answer to 4 decimal places.)

Probability

Answer 1

Number of ways in which r items can be selected from n, nCr = n!/(r! x (n-r)!)

Total number of trucks = 17

Number of trucks with brake problem = 6

Number of trucks without brake problem = 17 - 6 = 11

P(2 of the 4 trucks selected have brake problems) = Number of ways to select 2 trucks with brake problem from 6 x Number of ways to select 2 trucks without brake problem from 11 / Number of ways to select 4 trucks from total 17

= 6C2 x 11C2 / 17C4

= 15 x 55 / 2,380

= 0.3466