Question

The ratio of boys to girls in the Science Club is 3:5. If there are 60 girls, how many boys are there

Answer 1

25 boys.

15/3 = 5

5*5=25

Answer 2

In ratio 3:5
Lets take x1 as 3
Lets take x2 as 5
Lets take y1 as number of boys as y
Lets take y2 as number of girls as 60

x1:x2 :: y1:y2
Product of mean = Product of extremes
     x2*y1              = x1 * y2
       5*y                = 3*60
  5y  = 180
    y  = 180/5 = 36
    y2= 36

Therefore, the number of boys is 36 boys.  


Second question :
The point of 4th vertex is (-2,7)