AP EAMCET Engineering 22 Apr 2019 Shift 1 Paper

The event of expected to have children of both sexes is

1

2

.
So, the probability of children of both sexes is
1−[P(all‌boys)+P(all‌girls)] =1−{(

1

2

)4+(

1

2

)4}
=1−

1

16

−

1

16

=

7

8

So, the number of families expected to children of both sexes is, n=

7

8

×800=700