果园里有桃树x棵,梨树棵数比桃树棵数的3倍少20棵.梨树有 棵.当x=120时,梨树有 棵.
= :24=24: == %= (填小数)
1: ==25÷ = %=二成.
=40: = ÷40= %= (填小数)
=12: =1.2= ÷20= %
= (填小数)= 折.