my ans for P and C..Originally posted by teraexa:Exact area of R = pi - 2
P&C qn:
1)12!
2)6! x 2!
3)11!
4)5! x 6!
5)5! x 2!
for 2), i tink it's supposed to be 2^6?Originally posted by club18:my ans for P and C..
1) 12!
2) 6! x 6(2!)
3) 11!
4) forgot
5) 5! x 2!
i tink for both question 2 n 5 nid to x 2^6...cos deres 2 arrangement for each couple..cos this qn is in the tjc prelims 2007 which i tried..so quite sure of it..Originally posted by club18:my ans for P and C..
1) 12!
2) 6! x 6(2!)
3) 11!
4) forgot
5) 5! x 2!
Part 2 should be 6! x 2!, not 6! x 2^6. Here's the explanation:Originally posted by xxxshadowxxx:i tink for both question 2 n 5 nid to x 2^6...cos deres 2 arrangement for each couple..cos this qn is in the tjc prelims 2007 which i tried..so quite sure of it..
so for 2 shld be 6! x 2^6, 5.) 5! x 2^6..
eh..no offence bt 6 x 2! x 5 x 2! x 4 x 2! x 3 x 2! x 2 x 2! x 1 x 2!= 6! x (2!)^6=6!x2^6Originally posted by teraexa:Part 2 should be 6! x 2!, not 6! x 2^6. Here's the explanation:
Ok lets imagine 6 distinct groups first.
For the first slot, there are 6 possible combinations of groups to put into that slot. And then, within that group, you have 2! ways to arrange the people in the group.
For the 2nd slot, you have 5 possible groups to fit in now and again you have 2! ways to arrange the people in that group. Repeating this for the 4 remaining slots, the total combinations is 6 x 2! x 5 x 2! x 4 x 2! x 3 x 2! x 2 x 2! x 1 x 2! = 6! x 2!.
It's the same case for part 5 also.
Isn't ...Originally posted by teraexa:For the 2nd slot, you have 5 possible groups to fit in now and again you have 2! ways to arrange the people in that group. Repeating this for the 4 remaining slots, the total combinations is 6 x 2! x 5 x 2! x 4 x 2! x 3 x 2! x 2 x 2! x 1 x 2! = 6! x 2!.
thanks for the reminder. went to check with my friends. seem like i got my part iib wrong. that's 7 marks gone already.Originally posted by xxxshadowxxx:eh..no offence bt 6 x 2! x 5 x 2! x 4 x 2! x 3 x 2! x 2 x 2! x 1 x 2!= 6! x (2!)^6=6!x2^6
bt for part five i forget if dere is a nid for dem to alternate..i noe part 4 ask for alternate male n female if part 5 did ask for alternate den shld be 5!x2..if nt its 5! x 2^6
yup..seems like i got the 5! x 2! part wrong..didnt read the qn thoroughly..hahaOriginally posted by teraexa:thanks for the reminder. went to check with my friends. seem like i got my part iib wrong. that's 7 marks gone already.
but for part 5, my stand on 5! x 2! stands.