A spoonful of cream is taken from a cup of cream and put into a cup of coffee. The coffee is then stirred. Then a spoonful of this mixture is put into the cup of cream.
Is there now more cream in the coffee cup or more coffee in the cup of cream?
x = cup size
y = spoonfull
beginning ->
cup of coffee: x coffee 0 cream
cup of cream: x cream 0 coffee
add spoon of cream to coffee ->
cup of coffee: x coffee y cream
cup of cream: x - y cream 0 coffee
add spoon of mixed coffee to cream** ->
cup of coffee: x - y(x/(x+y)) coffee
y - y(y/(x+y)) cream
cup of cream: x - y + y(x/(x+y)) cream
y(x/(x+y)) coffee
y - y(y/(x+y)) = y(x/(x+y))
lets say y = 5
x = 10
5 - 5(5(/(10+5)) = 5(10/(10+5)
5 - 5(5/15) = 5(10/15)
5 - 25/15 = 50/15
75/15 - 25/15 = 50/15
50/15 = 50/15 CHECK
im too tired to do a generic check
using math x 2
