Please help . Put step by step workings please. Also I need help with both questions

You are on a cycling trip around europe with friends. you check the weather forecast for the first week. these are the temperatures for the week. sun mon tues wed thurs fri sat 16°c 20°c 24°c 28°c 28°c 23°c 15°c what is the mean temperature forecast for the week?

Asystem of equations has 1 solution. if 4x-y=5 is one of the equations , which could be the other equation ?

If chord ab is congruent to chord cd, then what must be true about ef and eg?