In a room, there are 450 students of which 20% are girls. a group of students have mobile phones with them, of which 40% are girls. of those students without a mobile phone, only 10% are girls. how many boys have mobile phones in that room?

90

Step-by-step explanation:

Total number of students = 450

20 % are girls

So, number of girls =

                               =

                               =

                               =

Now let no. of students having mobile phones be x

So, number of students not having mobile phones = 450-x

Now we are given that  A group of students have mobile phones with them, of which 40% are girls

So, This implies 60% of boys out of x having mobile phones.

So, number of girls having mobile phone =

Now we are given that Of those students without a mobile phone, only 10% are girls

So, number of girls not having mobile phone =

So, total number of girls :

=

=

=

=

=

=

So, Number of boys having mobile phone =

                                                                       =

Hence there are 90 boys have mobile phones in that room.

what is the approximate angle of acb if abc is 25cm and the length of segment bc is 15

step-by-step explanation: