The speed of the current in a river is 6 mph. a ferry operator who works that part of the river is looking to buy a new boat for his business. every day, his route takes him 22.5 miles against the current and back to his dock, and he needs to make this trip in a total of 9 hours. he has a boat in mind, but he can only test it on a lake where there is no current. how fast must the boat go on the lake in order for it to serve the ferry operator’s needs?

as we probably am aware that our atmosphere or air have various levels, each level has different gasses, and each gas has another porousness. at the point when the light originates from lower porousness to higher penetrability, it alters its course. with the goal that implies that when the light originates from the moon to the earth, it alters it's course a lot more occasions. it essentially implies that the state of the light piece of the moon is changed on the earth.

not copied too! hope this !

joke:

h o h o hope you have a merry christmas!