sat suite question viewer
Algebra
/ Linear equations in two variables
Difficulty: Medium
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 ?
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Explanation
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 
.