A soil supplement that weighs 15 lb contains iron, potassium, and mulch. The supplement contains twelve times as much mulch as iron and twice as much potassium

Question

math word problem

Answer 1

Let I=Iron, P=Potassium, M=Mulch

Solution is I=.8 lbs., P=4.7 lbs, M=9.5 lbs. rounded to one decimal place

I+P+M=15

M=12I, M=2P

You have 3 equations, 3 unknowns, and should get a unique solution, by substitution

Set 12I=2P, solve for P P=12I/2 = 6I

M=12I, I=M/12 P=6I=6(M/12) = M/2

I+P+M =15

M/12 + M/2 + M = 15

M/12 +6M/12 + 12M/12 = 15

19M/12=15

19M=180

M=180/19 = 9.47 pounds

M=12I 12I=180/19 I=15/19 = 0.79 pounds

M=2P 2P=180/19 P=90/19 = 4.74 pounds

15/19 + 90/19 + 180/19 = 285/19 = 15 = I+P+M