The complete question in the attached figure
we have that
x----------------> r<span>epresents the number of spoonfuls of brand A
</span>y----------------> represents the number of spoonfuls of brand B
<span>Brand A---------------- > Calcium. Iron Vitamins ------ > 5 4 7 </span><span>milligrams
</span>Brand B---------------- > Calcium. Iron Vitamins ------ > 4 6 4 milligrams
<span>Steve needs to take at least
</span>Calcium milligrams >=24
Iron milligrams >=15
Vitamins milligrams >=16
I proceed to calculate the system inequalities
for Calcium
5x+4y>=24
for iron
4x+6y>=15
for Vitamins
7x+4y>=16
using a graph tool to solve the system of inequalities
see the attached figure
the answer is the point (1,5) and the point (4,1) are solution