I need assistance with this stats problem Its short and shou

I need assistance with this stats problem. It\'s short and should be simple, but I can\'t seem to figure it out.

Thirty percent of all telephones of a certain type are submitted for service while under warranty. Of these, 60% can be repaired, whereas the other 40% must be replaced with new units. If a company purchases ten of these telephones, what is the probability that exactly two will end up being replaced under warranty? (Round your answer to three decimal places.)

Solution

total no of phone purchased=10 i.e. n=10

we have to find out for exactly 2phones that will be replaced so k=2
toatl no of permuatations are n!/k!(n-k)!=10!/2!8!=45

for exactly two phones being replaced,probability=(probability of replace)².(probability of repair)⁸.45

=(0.4)².(0.6)⁸.45=0.1208=12.08%