Answer:
A=5, B=10 and C=15
Step-by-step explanation:
-We are given that:
[tex]A+B+C=30\\\\A+B=C\\\\\therefore 2C=30\\\\C=15\\\\A+B=30-15=15\ \ \ \ ...i[/tex]
-Also, given that:
[tex]10A+12B+15C=395, \ C=15\\\\10A+12B=395-15\times 15\\\\10A+12B=170\ \ \ \ \ \ ...ii[/tex]
From equation i, we have that:
[tex]A=15-B[/tex]
#we substitute A=15-B in equation ii to solve for B:
[tex]10A+12B=170\\\\10(15-B)+12B=170\\\\150A-10B+12B=170\\\\2B=20\\\\B=10\\\\\therefore A=15-10=5[/tex]
Hence, the values of our unknowns are A=5, B=10 and C=15