On a 210-mile trip, Cameron drove at an average speed of 60 miles per hour for the first x hours. He then completed the trip, driving at an average speed of 50 miles per hour for the remaining y hours. If , what is the value of y ?
The correct answer is 3. It’s given that Cameron drove 60 miles per hour for x hours; therefore, the distance driven at this speed can be represented by . He then drove 50 miles per hour for y hours; therefore, the distance driven at this speed can be represented by
. Since Cameron drove 210 total miles, the equation
represents this situation. If
, substitution yields
, or
. Subtracting 60 from both sides of this equation yields
. Dividing both sides of this equation by 50 yields
.