A causal friend might be a friend of a friend or someone that is in your class who you talk two once a week or less. A close friend knows all about you, defends you and you talk to every time you get a chance.
Answer:
the cycle of processes by which water circulates between the earth's oceans, atmosphere, and land, involving precipitation as rain and snow, drainage in streams and rivers, and return to the atmosphere by evaporation and transpiration.
Explanation:
$ you have will be represented by y
$ your friend has will be f
The amount of weeks you save up for will be w
y=55+10w
f=20+15w
now set them equal to each other
55+10w=20+15w
Move all variables to one side and all constants to the other
55-20=15w-10w
combine like terms
35=5w
isolate the variable
35/5=w
combine like terms
7=w
it will take 7 weeks