1) In a school of 3600 students, number of boys is twice the number of girls. Find the number of girls.

1200

Step-by-step explanation:

x is the number of boy

The number of boys is twice the number of girls:

Total is 3600 students: x + = 3600 → x = 2400

Therefore, the number of girls is: 2400/2= 1200

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so:

the final price would be 29.6925

step-by-step explanation:

39.59 minus 25% equals 29.6925