Joe has 7 shirts, each a different color. He randomly selects 3 shirts to pack
for a trip. What is the probability that he packs the blue, yellow, and white
shirts?
7!/3!(7-3!)= 7!/3!x4!= 7x6x5x4x3x2x1/(3x2x1)x(4x3x2x1)= 210/6= 35
Is this correct?

Question

Joe has 7 shirts, each a different color. He randomly selects 3 shirts to pack
for a trip. What is the probability that he packs the blue, yellow, and white
shirts?
7!/3!(7-3!)= 7!/3!x4!= 7x6x5x4x3x2x1/(3x2x1)x(4x3x2x1)= 210/6= 35
Is this correct?

anonymous · Answer

are you using some theorem?

anonymous · Answer

how are you trying to solve this?

j.f · Answer

I'm following the definition of Combinations, where nCr= n!/r!(n-r)!

directrix · Answer

I did this:   (C(3,3) *C (4,0)) / C(7,3) and got 1/35

C(3,3) --> blue, yellow, and white shirts 
C (4,0) --> 0 of the remaining 4 colors of shirts

C(7,3) -->  number of ways to choose group of 3 shirts from 7 shirts

@J.F