Maths-
General
Easy
Question
A class contains 4 boys and g girls. Every Sunday five students, including at least three boys go for a picnic to Appu Ghar, a different group being sent every week. During, the picnic, the class teacher gives each girl in the group a doll. If the total number of dolls distributed was 85, then value of g is -
- 15
- 12
- 8
- 5
The correct answer is: 5
Number of groups having 4 boys and 1 girl
= (4C4) (gC1) = g
and number of groups having 3 boys and 2 girls
= (4C3) (gC2) = 2g(g – 1)
Thus, the number of dolls distributed
= g(1) + (2)[2g (g – 1)]
= 4g2 – 3g
We are given 4g2 – 3g = 85 
g = 5.
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