Question

in a school the ratio of boys to girls is 5:3.if there are 115 boys find the number of girls

Answer 1

Let the number of girls be x

So 115:x = 5:3

or,

115 : x :: 5 : 3

We know that, product of extreme = product of mean

=> 115 × 3 = 5x

=> 5x = 115 × 3

=> x = 115 × 3/5

=> x = 23 × 3

=> x = 69


So number of girls = 69

Hope it helps dear friend ☺️✌️

Answer 2

solution:

The ratio of girls to boys is 5:3, or five to three. This means that for every 5 boys, there are 3 girls in the class. We can think of the boys as being in "groups" of 5. For every group of 5 boys, there will be a group of 3 girls.

 

How many groups of 5 boys are in the classroom? There are 15 boys, which means there are 3 groups of 5 (5 times 3 equals 15). Since there are 3 girls for every 5 boys, this means there are also 3 groups of girls, but there are 3 girls in each group instead of 5. 3 times 3 equals 9, so there are 9 girls.  

 

Total students equals 15 plus 9, or 24.

 

 

Another way of thinking about this is by cross multiplying. 3/5 = g/15 (make sure you keep the boys and girls in the same order. Girls are in the numerator, boys are in the denominator for both). When you cross multiple, you get 3 * 15 = 5*g. Solve for g, and you get g = (3 * 15) / 5, or 45 / 5, or 9. Add 9 to the 15 boys for the total, and you get 24.