A sample of 4 different calculators is randomly selected from a group containing 16 that are defective and 30 that have no defects. What is the probability that at least one of the calculators is defective?

0.819
0.168
0.160
0.832

Question

A sample of 4 different calculators is randomly selected from a group containing 16 that are defective and 30 that have no defects. What is the probability that at least one of the calculators is defective? 
  
 0.819 
 0.168 
 0.160 
 0.832

jim_thompson5910 · Answer

are you familiar with the combination formula?

anonymous · Answer

no :o

jim_thompson5910 · Answer

so this formula on the link below isn't familiar? http://www.mathwords.com/c/combination_formula.htm

anonymous · Answer

not at all

jim_thompson5910 · Answer

what kind of calculator do you have?

anonymous · Answer

a basic phone calculator lol

jim_thompson5910 · Answer

ok use this calculator http://www.calculatorsoup.com/calculators/discretemathematics/combinations.php

jim_thompson5910 · Answer

type in 30 for n and 4 for r

what number do you get?

anonymous · Answer

27405

jim_thompson5910 · Answer

that's the number of ways to pick 4 nondefective calculators

jim_thompson5910 · Answer

now do n = 46 and r = 4

anonymous · Answer

163185

jim_thompson5910 · Answer

Now divide

27405/163185 = 0.1679382296167

that is the probability of picking 0 defective calculators

subtract from 1

1-0.1679382296167 = 0.8320617703833

which rounds to 0.832

this is the probability of picking at least one defective calculator

anonymous · Answer

thank you ! (:

jim_thompson5910 · Answer

yw

anonymous · Answer

Prob(at least)=1-prob(at most)
Where events are opposite in nature