exam Maths Puzzle

Out of eight crew members three particular members can sit only on the left side. Another two particular members can sit only on the right side. Find the number of ways in which the crew can be arranged so that four men can sit on each side.

A.

864

B.

863

C.

865

D.

1728

Read Solution (Total 2)

3!*4!*3*=864.on each side 3 members can sit at 3! places .at middle places 4 members can sit at 4! places.so ans is 864
8 years agoHelpfull: Yes(2) No(0)

Left side of boat already 3 selected.
Right side of boat already 2 selected.
So we have 3 member to select 1 for left and 2 for right.
For first left selection-3C1.
For right selection we have no option to chose as 3c2 . so we
choose as 2c2.
For left side 4 crew arranged as 4!
For right side 4 crew arranged as 4!
so resultant ways-3c1*4!*4!=1728
SECONDLY
Similarly if we take first right crew selection then 3c2*4!*4!=1728
5 years agoHelpfull: Yes(0) No(0)

exam Other Question

A box contains 10 balls out of which 3 are red and rest are blue. In how many ways can a random sample of 6 balls be drawn from the bag so that at the most 2 red balls are included in the sample and no sample has all the 6 balls of the same colour?

A.

105

B.

168

C.

189

D.

120 A man positioned at the origin of the coordinate system. the man can take steps of unit measure in the direction North, East, West or South. Find the number of ways of he can reach the point (5,6), covering the shortest possible distance.

A.

252

B.

432

C.

462

D.

504