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 .
( x + 4 ) × 60 + x × 120 + ( x − 4 ) × 180 / ( x + 4 ) + x + ( x − 4 ) = 100 ⇒ 360 x − 480 / 3 x = 100 ⇒ 60 x = 480 ⇒ x = 8 answer c
divide(subtract(multiply(180, 4), multiply(60, 4)), subtract(add(add(60, 120), 180), multiply(100, const_3)))