The probability of sales representative making a sale with any one customer is $\frac{1}{3}$. The sales representative makes eight contacts a day. To find the probability of making four sales, evaluate the term

$$8{C}_{4}(\frac{1}{3}{)}^{4}(\frac{2}{4}{)}^{4}$$

In the expansion $$(\frac{1}{3}+\frac{2}{3}{)}^{8}$$

I know how to evaluate $$8{C}_{4}(\frac{1}{3}{)}^{4}(\frac{2}{4}{)}^{4}$$ but I don't understand what they mean by " in the expansion of $$(\frac{1}{3}+\frac{2}{3}{)}^{8}$$