Question 1172204
L for $10 per kg
H for $0.15 per kg
T for 0.13 per kg
M  for 300 kg
y for how much kg of the 0.15 dollar per kg granite


{{{Hy+L(M-y)=TM}}}
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{{{Hy+LM-Ly=TM}}}
{{{(H-L)y+LM=TM}}}
{{{(H-L)y=M(T-L)}}}

{{{highlight(y=M((T-L)/(H-L)))}}}------Your choice if you want to substitute the given values first, or in this formula here.  Find y, and evaluate M-y.