Sammy and david were selling water bottles to raise money for new football uniforms. Sammy sold 5 bottles for every 3 water bottles. David sold. Together. They sold 160 water bottles. How many did each boy sell?

X=number of bottles sold by Sammy.

y=number of bottles sold by David.

We can suggest the following system of equations:

x/y=5/3

x+y=160

We solve the system of equations by substitution method.

x+y=160 ⇒y=160-x

x / (160-x) = 5/3

3x=5 (160-x)

3x=800-5x

3x+5x=800

8x=800

x=800/8

x=100

y=160-x

y=160-100

y=60

answer: Sammy sold 100 bottles and David sold 60 bottles.

other method.

5x=bottles sold by Sammy

3x=bottles sold by David.

We can suggest the following equation:

5x+3x=160

8x=160

x=160/8

x=20

bottles sold by Sammy: 5x=5 (20) = 100

bottles sold by David: 3x=3 (20) = 60

Answer:Sammy sold 100 bottles and David sold 60 bottles.