Grade Levels: 8th Grade, 9th Grade, 10th Grade, 11th Grade, 12th Grade,
Topics: AlgebraExpressions and Equations
Common Core State Standard: A-CED.2, A-CED.4,
Knowledge and Skills:

· Can evaluate expressions by substituting values for variables
· Can simplify expressions using correct order of operations
· Can do basic operations on both sides of an equation in such a way as to preserve the equality

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Response Time

If you send a signal over a fiber optic cable to another computer and get a response, the response time, tresponse, depends on three things:

a) the distance between you and the computer, L

b) the velocity of light traveling through the cable, v

c) the amount of time it takes the other computer to process your signal, tprocessing

The equation you would use to find the response time is this:

Note that the velocity of light in fiber optic cable, v, is about 2/3 of the velocity of light in a vacuum, which makes it approximately equal to 200,000,000 meters/second.

1. Calculate tresponse for the given values of L and tprocessing:

L tprocessing tresponse
500,000 meters 0.013 seconds
8,000,000 meters 0.005 seconds
2,000 meters 0.002 seconds
20,000,000 meters 0.04 seconds

2. Solve the equation to find the unknown value:

L tprocessing tresponse
750,000 ? 0.0325
? 0.001 0.00195
? 0.015 0.016
50,000,000 ? 0.503