A rectangular swimming pool is 10 feet by 12 feet. A deck that has uniform width surrounds the pool. The total area of the pool and deck is 360 square feet. What is the width of the deck?
Select
A) 7 B) 2 C) 3 D) 4 E) 6

Rationale: "let the width = w total area of the pool and deck = ( 2 w + 10 ) ( 2 w + 12 ) we can test the answer choices along with unit digit method a ) 2 feet . . . . . . . . . . . 14 * 16 has unit digit 4 . . . . . . . . . . eliminate b ) 2.5 feet . . . . . . . . . 15 * 17 has unit digit 5 . . . . . . . . . . eliminate c ) 3 feet . . . . . . . . . . . . 16 * 18 has unit digit 8 . . . . . . . . . . . eliminate d ) 4 feet . . . . . . . . . . . . 18 * 20 has unit digit 0 . . . . . . . . . . . hold e ) 5 feet . . . . . . . . . . . . 20 * 22 has unit digit 0 . . . . . . . . . . . eliminate ( bigger size ) answer : d w = 4"
Answer: D