AP EAPCET 24-Aug-2021 Shift 1 Paper

Let success is to select a smart phone and it is for office purpose.
∴ p=

1

2

,q=1−p=1−

1

2

=

1

2

Now, probability that out of 10 users exactly 2 of them use for office purpose
= Probability of setting exactly 2 success out of 10 trial
=‌10C2.p2q8[∵[P(X=r)=‌nCrpr.qn−r]
=‌10C2.(

1

2

)2(

1

2

)8=‌10C2(

1

210

)