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.

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step-by-step explanation: