设甲乙剩余部分x天完成.
2×(1/20+1/25)+(1/25+1/20)x=1
9/50+9/100x=1
9/100x=1-9/50
9/100x=41/50
x=41/50×100/9
x=82/9
答:甲乙剩余部分82/9天完成.