设上坡路xkm,平路ykm.
(x/3)+(y/4)=54/60①,(y/4)+(x/5)=42/60②.
①×60,得20x+15y=54③,②×60,得15y+12x=42④.
③-④,得8x=8,x=1⑤.
⑤代入②,得15y+12=42,y=2.
∴上坡路1km,平路2km.∴甲乙全程为1+2=3(km).
答:甲乙全程为3km.
设上坡路xkm,平路ykm.
(x/3)+(y/4)=54/60①,(y/4)+(x/5)=42/60②.
①×60,得20x+15y=54③,②×60,得15y+12x=42④.
③-④,得8x=8,x=1⑤.
⑤代入②,得15y+12=42,y=2.
∴上坡路1km,平路2km.∴甲乙全程为1+2=3(km).
答:甲乙全程为3km.