Question

A 2,000-foot-long fence will be used to enclose a rectangular field that is three times as long as it is wide. What is the length of the field?

Answer 1

The answer to this question would be: 750ft
In this question, you are given the rectangle perimeter (2,000 ft) and the ratio of rectangle length:width (3:1). The equation of this question should be:

3*rectangle width = 1 *rectangle length 
rectangle width = 1/3 rectangle length

rectangle perimeter = 2,000ft

Then using the rectangle formula, you will be able to find the length. It would be:
rectangle perimeter = 2* (length+width)
2,000ft /2 = 1/3 length + length
1 1/3 length= 1,000ft
length = 1,000ft /4 *3= 750ft