Answer: 200cm long
Step-by-step explanation:
Let the length of the rod be x
red = 1/4 of the rod , which means 1/4 of x
orange = 2/5 of x
The remainder = x - ([tex]\frac{x}{4}[/tex] +[tex]\frac{2x}{5}[/tex])
= x - ([tex]\frac{13x}{20}[/tex])
= [tex]\frac{7x}{20}[/tex]
yellow = 2/7 of the remainder , that is
yellow = 2/7 of [tex]\frac{7x}{20}[/tex]
yellow = [tex]\frac{x}{10}[/tex]
and it was given that the yellow section was 20cm long , that is
[tex]\frac{x}{10}[/tex] = 20cm
x = 20 x10
x = 200
Therefore the rod was 200cm long
