In a coconut grove, (x + 2) trees yield 30 nuts per year, x trees yield 120 nuts per year and (x – 2) trees yield 180 nuts per year. If the average yield per year per tree be 100, find x. Choose the correct option.
A) 3  B) 4  C) 5  D) 6  E) 10
(x+2)×30+x×120+(x−2)×180/(x+2)+x+(x−2)=100   ⇒ 330x−300/3x = 100   ⇒ 30x = 300 ⇒ x = 10   Answer 10
<result>E</result>
In a coconut grove, (x + 2) trees yield 30 nuts per year, x trees yield 120 nuts per year and (x – 2) trees yield 180 nuts per year. If the average yield per year per tree be 100, find x.