Question

Each red stick is 4 cm longer than each blue stick. Five red sticks and two blue sticks together measure exactly 100 cm. How long is the blue stick?

Answer 1

x= red stick
y= blue stick

Set up a system of equations:
y+4=x
5x+2y=100

Substitute in:
5(y+4)+2y=100
5y+20+2y=100
7y=80
y=80/7=11 3/7 cm

The blue stick is 11 3/7 cm

Hope this helped!