In a coconut grove, (x + 4) trees yield 60 nuts per year, x trees yield 120 nuts per year and (x – 4) trees yield 180 nuts per year. If the average yield per year per tree be 100, find x. Choices.
A) 3	B) 4	C) 8	D) 9	E) None of the above
(x+4)×60+x×120+(x−4)×180/(x+4)+x+(x−4)=100   ⇒ 360x−480/3x = 100   ⇒ 60x = 480 ⇒ x = 8   Answer 8
<result>C</result>
In a coconut grove, (x + 4) trees yield 60 nuts per year, x trees yield 120 nuts per year and (x – 4) trees yield 180 nuts per year. If the average yield per year per tree be 100, find x.