现在有ABC三个阀门,三个全部打开1小时注满水,只打开AC打开,需1.05小时,只打开BC,需2小时,

1/A+1/B+1/C=11/A+1/C=1/1.05=20/211/B+1/C=1/2 1/A+1/B+2/C=20/21+1/2=40/42+21/42=61/421/C=61/42-1=19/42 C=42/191/A=20/21-19/42=40/42-19/42=21/42=1/2 A=21/B=1/2-19/42=21/42-19/42=2/42=1/21 B=21