Mr. young has a piece of rope. He uses 1/4 of it to tie some boxes together. He then uses 5/9 of the remainder to make a jumprope for his daughter. After this, 120 centimers are left. What is the length of rope Mr. Young used to tie the boxes together?

We have:

x = the amount of rope.

x (boxes) = the amount of rope used to tie the boxes together.

Then, we have the following equation:

x - (1/4) x-5/9 (x - (1/4) x) = 120

(x-4/x) - (5x/9) + (5x/36) = 120

(1/3) x=120

x=120x3

x=360 cm

x (boxes) = (1/4) 360

x (boxes) = 360/4

x (boxes) = 90 cm

What is the length of rope Mr. Young used to tie the boxes together?

The lenght of rope Mr. Young used to tie the boxes together is: 90 cm.