To get he maximum value of C=6x+2y
We need to get the highest possible value for x, which is 5
Now for highest possible value of y we need to solve equation 4x-y>1
We took x=5,
Sp, 4(5)-y>1
20-1>y
So highest possible value of y is 19
We will now substitute highest values of x and y in the main equation.
C=6(5)+2(19)=30+38=68
Hence, the highest possible value of C is 68.