问题 解答题 已知12:x=0.2:0.3,则x的值为( )A.34B.43C.3 答案 12:x=0.2:0.3, 0.2x=0.3×12, 0.2x=0.15,0.2x÷0.2=0.15÷0.2, x=34,故选:A.