in a coconut grove , ( x + 1 ) trees yield 60 nuts per year , x trees yield 120 nuts per year and ( x – 1 ) trees yield 180 nuts per year . if the average yield per year per tree be 100 , find x .
"( x + 1 ) × 60 + x × 120 + ( x − 1 ) × 180 / ( x + 1 ) + x + ( x − 1 ) = 100 ⇒ 360 x − 120 / 3 x = 100 ⇒ 60 x = 120 ⇒ x = 2 answer a"
divide(subtract(multiply(180, 1), multiply(60, 1)), subtract(add(add(60, 120), 180), multiply(100, const_3)))