饲养场养鸡350只,比鸭少6分之1,鸭比鹅多5分1,鹅有多少只
鸭 = 350 ÷ (1- 1/6 )
= 350 x 6/5
= 420
鹅 = 420 ÷ ( 1+ 1/5)
= 420 x 5 / 6
= 350