The length of the straight part of a river is three times shorter than the crooked part. If the river is 80 miles long, how long is the straight part of the river? Give me reasons, before answering the question
Let's say the river's length in the straight part of the river is x. The total length of the river is the length of the straight part plus 3 times the length of the straight part for the crooked part, which is x + 3x = 80. The total length of the river is 4x = 80. The straight part of the river is x = 80 / 4 = 20 miles. So the final answer is 20.