Problema Solution
One type of fertilizer has 30% nitrogen and another type of fertilizer has 15% nitrogen. If a farmer needs 600 kg of fertilizer that has 20% nitrogen, how much of each type of fertilizer should he mix together?
Answer provided by our tutors
let
x = kg of the 30% nitrogen fertilizer
y = kg of the 15% nitrogen fertilizer
the farmer needs total of 600 kg fertilizer
x + y = 600
30% of x nitrogen + 15% of y nitrogen = 20% of 600 nitrogen
0.3x + 0.15y = 0.2*600
0.3x + 0.15y = 120
by solving the system of equations
x + y = 600
0.3x + 0.15y = 120
we find
x = 200 kg
y = 400 kg
200 kg from the 30% nitrogen fertilizer should be mixed with 400 kg from the 15% nitrogen fertilizer.