math
posted by john .
A rectangular garden is 20 m by 25m. It is surrounded by a sidewalk. The outside perimeter of the sidewalk is 114m. What is the width of the sidewalk?

let the width of the sidewalk be x m
new dimensions:
20+2x by 25+2x
2(20+2x) + 2(25+x) = 114
40 + 4x + 50 + 4x = 114
8x = 24
x = 3
the sidewalk is 3 m wide.