Given:
c1=0.0825 M
c2=0.7280 M
c3=0.1 M
V3 =1 dm3
Setting up the equation:
c1V1+c2V2 = c3V3
now you work a little magic:
V1+V2=V3
Solving for V1
V1= V3 - V2
substitute V1 in first equation:
c1(V3-V2) + c2V2=c3V3
Solving:
c1V3-c1V2 + c2V2=c3V3
Rearranging the values:
c1V3-c3V3=c1V2-c2V2
V3(c1-c3)=V2(c1-c2)
So,
V2 = V3(c1-c3) / c1-c2
Substituting known values:
V2= 1 dm3 * (0.0825-0.1) / 0.0825 - 0.7280
and you get:
V2= 0.027 dm3
Hence,
V1 = V3-V2
V1
= 0.973 dm2