Question
Imagine that you have ten small light bulbs, of which three are burned out a) in how many ways can you randomly select 4 of the light bulb b) in how many ways can you select two good light bulbs and two burned out light bulbs?
Hel needed Urgently
Hel needed Urgently
Answers
Kabir
a) In order to find the ways you can randomly select 4 of them, we use Combinations:
C(10,4)
= 10!/6!4! = 210
b) Two select in a specific way, we use different combinations for the burnt out and good bulbs, and multiply them:
C(7,2) x C(3,2)
= 7!/5!2! x 3!/2!
= 7 x 3 x 3
= 63
C(10,4)
= 10!/6!4! = 210
b) Two select in a specific way, we use different combinations for the burnt out and good bulbs, and multiply them:
C(7,2) x C(3,2)
= 7!/5!2! x 3!/2!
= 7 x 3 x 3
= 63