PNC (aptitude)

Question

Arrange 8 cars such that there are exactly 4 cars between 2 specified cars.

Comments

$3 \times 2 \times 6!$

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brother, i hope remaining cars are identical to each other.

then it is 3*2! = 6

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@shivani is it 6×6!

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If two cars are prespecified then  2*⁶ C ₄ * 4!   ( assumed that cars are identical )

Answer 1

see, first satisfy the first condition --between two specified cars there should be

exactly 4 cars so posiible ways can be ->1)  # __ __ __ __ #__ __(# denote the specified cars)

                                                                  2)__@ __ __ __ __ @__

                                                                   3)__ __ % __ __ __ __ %

so , we have 3 ways for selection of parking slots for two cars now these two cars can also arrange in 2 ways __@ __ __ __ __ @__ =3.2!

now we are left with 6 positions and 6 cars can be parked in 6! ways

now, all 8 have to be  parked so it is going to be 6.6!(answer)

Comments

@Sindhiya best explaination thnxx :)