$$Let\ the\ total\ revenue\ =20\ $$
$$\frac{1}{3}of\ \ revenue\ from\ last\ quarter\ from\ foreign\ client$$
$$foreign\ client=\frac{1}{3}\cdot20=\frac{20}{3}=6.67$$
$$\frac{1}{4\ }of\ their\ revenue\ \ from\ out\ of\ the\ state\ clients\ $$
$$=\frac{1}{4}\cdot20=\frac{20}{4}=5$$
In State client revenue = Total revenue - [sum of revenue from foreign and out of state clients]
In State client revenue $$=20-\left[6.67+5\right]=11.67$$
In State client revenue $$\%=\frac{11.67}{20}\cdot100=58.35\%$$
Question says company get 13 of its revenue from last quarter from foreign clients not workable because the total of foreign clients was not obtained, A typographical error was observed on 1/3 as 13.