Hai voi cung chay sau 10 gio thi day be
=>hai voi cung chay thi moi gio duoc 1/10 be
=>2 voi cung chay sau 4 gio thi chay duoc 4/10 be =>sau 4 gio chay chung thi voi thu 2 phai chay 1 - 4/10 = 6/10 be ma voi thu 2 chay mat 18 gio =>moi gio voi thu 2 chay duoc 6/10 : 18 = 1/30 be ma ca hai voi moi gio chay duoc 1/10 be
=>moi gio voi thu nhat chay duoc 1/10 - 1/30 = 1/15 be
minh viet khong dau mong ban hieu cho