一个池上装有3根水管。甲管为进水管,乙管为出水管,20分钟可将满池水放完,丙管也是出水管,30分钟可将满池水放完。现在先打开甲管,当水池水刚溢出时,打开乙,丙两管用了18分钟放完,当打开甲管注满水是,再打开乙管,而不开丙管,多少分钟将水放完?7M;J5v7w,K0F(~(@+G1p0A
解:
算式:提示3w0X1s(i2i7^;a3o+p6c-`-i/C/M.E9K+d7M;J5v7w,K0F(~(@+G1p0A
答:;@(M2K(I;c0l(S*X'z2D8^)Y:{2}.?4}'Y6g分钟将水放完。7M;J5v7w,K0F(~(@+G1p0A