The ratio of the number of boys and girls in a college is 7:8. If the percentage increase in the number of boys and girls be 20% and 10% respectively, what will be the new ratio?

Step-by-step explanation:

Boys : Girls = 7 : 8

Let the number of boy = 7x

The number of girls = 8x

Number of boys after 20% increase = 120% of 7x

                                                            = 1.2 * 7x

                                                             = 8.4 x

Number of girls after 10% increase = 110% of 8x

                                                           = 1.1 * 8x

                                                           = 8.8x                    

After increase in number of boys & girls = 8.4x : 8.8x

                      = 84 : 88    { reduce to simplest form by giving by 4th table}

                     = 21 :  22

if x = 1, then the answer is 3.5