Question

Lisa uses 2 pieces of copper wire, each 9 feet long, for

each robot she builds. If she started with a 500-yard roll
of copper wire, which of the following represents the
number of yards of wire left on the roll after Lisa built r
robots? (3 feet = 1 yard)

Answer 1

500 - 6r = t

Explanation:

500 represents the amount of copper wire Lisa started with.

-6r represents how much copper wire (in yards) is used on the robot (9*2 / 3 = 6).

t represents the total wire left after Lisa builds r robots.