Question

两地相距60千米,甲船逆流而上要行15小时,顺流而下要行10小时,乙船逆流而上要行6小时,它顺流而下要行多

Answer 1

60÷[60÷6+(60÷10-60÷15)]

=60÷[60÷6+(6-4)]

=60÷(60÷6+2)

=60÷(10+2)

=60÷12

=5(小时)

答：它顺流而下要行5小时.