Let the income of A be \( I$_$A \) and the income of B be \( I$_$B \). According to the question:
\[
I_A = \frac{2}{3} I$_$B
\]
Let the expenditure of A be \( E$_$A \) and the expenditure of B be \( E$_$B \). We are given:
\[
E$_$A = \frac{3}{4} E$_$B
\]
Additionally, we know that one-third of income of B is equal to the expenditure of A, i.e.,
\[
\frac{1}{3} I$_$B = E$_$A
\]
Substitute the value of \( E$_$A \):
\[
\frac{1}{3} I$_$B = \frac{3}{4} E$_$B
\]
From this, calculate the ratio of savings of A and B using their respective incomes and expenditures.
The final ratio of savings will be \( 3 : 5 \).