Question

If 36% of pupils in a school are girls and the number of boys in the school is 816,how many girls are there in the school (1) 459 (2)357 (3) 457 (4) 359 ​

Answer 1

Let, the total number of students be,'x'

So, the number of girls= (x*36/100)

                                     = 9x/25

The number of boys = (x-9x/25)

                                 = (25x-9x)/25

                                = 16x/25

By condition,

16x/25=816

or, 16x= 816*25

or, x = 816*25/16

or, x = 204*25/4

or, x = 51*25

or, x = 1275

So, total number of students is 1275

Therefore, the number of girls = (1275*36/100)

                                                   = (1275*9/25)

                                                    = (51*9)

                                                     = 459

(Ans): (1) 459

Answer 2

100%-36%=64%

64%=816

1%=816/64=12.75

so, 36%=12.75*36=459