Question

A class consists of 4 boys and p girls...Every Sunday 5 students including at least 3 boys go for a picnic..to X place..A different group being sent every week.During the picnic the class teacher gives each girl int he group a doll..If the total no. of dolls distributed was 85..then p=?

Answer 1

@hartnn :O

Answer 2

@ghazi

Answer 3

I made two cases..
Since in total we have 4 boys and p girls...
i) 3 boys and 2 girls => 4C3 x pC2=>2p(p-1)
ii) 4 boys and 1 girl => 4C4 x pC1=>p
I don't know how to distribute the dolls only to the girls..
in the book its written :
1 x p + 2 x [2p(p-1)] = 85
why did they multiply 2 ?

Answer 4

My only reasonable is between the 2 girls A or B, we divide into 2 sub cases. That why they multiply 2!

Answer 5

:o

Answer 6

Either A then B or B then A

Answer 7

okay