Question

The ratio of number of boys to the number of girls in a school of 1440 students is 7:5 . If 40 new boys are admitted, find how many new girls may be admitted to make this ratio 4:3.​

Answer 1

Let boys = 7x

and girls = 5x

so total = 12x

Total students before new addmission = 12x = 1440

x = 120

boys = 7x = 7×120 = 840

girls = 5x = 5×120 = 600

Now new students addimitted

boys = 840+40 = 880

girls = 600+g

and the given ratio = 4:3

880/600+g = 4/3

220/600+g = 1/3

600+g = 660

g = 660-600

g = 60