l varies directly as m and l is equal to 5, when , find l when .

If x varies inversely as y and x = 20 when y = 600, find y when x = 400.

The variable x varies directly as y and x = 80 when y = 160, What is y when x is 64.

If x varies inversely as y and y = 60 when x = 1.5, find x when y = 4.5.

In a camp, there is enough flour for 300 persons for 42 days. How long will the flour last if 20 more persons join the camp?