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Algebra / Systems of two linear equations in two variables Difficulty: Medium

A bus traveled on the highway and on local roads to complete a trip of 160 miles. The trip took 4 hours. The bus traveled at an average speed of 55 miles per hour mph on the highway and an average speed of 25 mph on local roads. If x is the time, in hours, the bus traveled on the highway and y is the time, in hours, it traveled on local roads, which system of equations represents this situation?

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Explanation

Choice B is correct. If the bus traveled at an average speed of 55 miles per hour mph on the highway for x hours, then the bus traveled 55 x miles on the highway. If the bus traveled at an average speed of 25 mph on local roads for y hours, then the bus traveled 25 y miles on local roads. It's given that the trip was 160 miles. This can be represented by the equation 55x+25y=160. It's also given that the trip took 4 hours. This can be represented by the equation x + y = 4 . Therefore, the system consisting of the equations 55x+25y=160 and x + y = 4 represents this situation.

Choice A is incorrect. This system of equations represents a situation where the trip was 4 miles and took 160 hours.

Choice C is incorrect. This system of equations represents a situation where the trip was 4 miles and took 160 hours, and the bus traveled at an average speed of 25 mph on the highway and 55 mph on local roads.

Choice D is incorrect. This system of equations represents a situation where the bus traveled at an average speed of 25 mph on the highway and 55 mph on local roads.