Concept:
Convert the given percentage relations into fractional ratios and then combine the ratios by making the common term equal.
Step 1: Finding the ratio between A and B.
\[
\frac{A}{3}=70\%\text{ of }B=\frac{7}{10}B
\]
\[
A=\frac{21}{10}B
\]
\[
A:B=21:10
\]
Step 2: Finding the ratio between C and A.
\[
\frac{2}{3}C=25\%\text{ of }A=\frac{1}{4}A
\]
\[
C=\frac{3}{8}A
\]
\[
C:A=3:8
\]
Step 3: Combining the ratios.
\[
A:B=21:10
\]
\[
A:C=8:3
\]
LCM of 21 and 8 is 168.
\[
A:B=168:80
\]
\[
A:C=168:63
\]
Hence,
\[
A:B:C=168:80:63
\]
{168:80:63}