Math
posted by Curt on .
A store mixes Brazilian coffee worth $10 per kilogram and Turkish coffee worth $12 per kilogram. The mixture is to sell for $11 per kilogram. Find out how much of each should be used to make a 216 kilogram mixture.

216 / 2 = ?

Ms. Sue is correct. Since $11 is halfway between $10 and $12, there is an equal amount of each coffee.
algebraically, consider the value of each component, and the total. If there are x kg of Brazilian coffee, then there are 216x kg of Turkish.
10x + 12(216x) = 11*216
x = 108
This method will also work if the price ratio were different.