(1)设甲种货车每辆载重x吨,乙种货车每辆载重y吨,
则
,
解之得
.
答:甲种货车每次运货5吨,乙种货车每次运货3.5吨.
(2)5×3+3.5×5=32.5(吨),32.5×30=975(元).
答:货主应付运费975元.