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

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

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