Lets assume, Sally has X pound of potatoes in her pantry.
So, 4/3 of the potatoes Sally has in her pantry = [tex] \frac{4}{3}X [/tex]
Now, Sally needs 2/3 pound of potatoes and this 2/3 pound of potatoes is 1/3 pound more than that [tex] \frac{4}{3}X [/tex]
So the representing equation will be:
[tex] \frac{2}{3} = \frac{1}{3}+ \frac{4}{3}X [/tex]
[tex] \frac{2}{3} - \frac{1}{3} = \frac{4}{3} X [/tex] (subtracting [tex] \frac{1}{3} [/tex] from both sides)
[tex] \frac{1}{3}= \frac{4}{3}X [/tex]
[tex] 1= 4X [/tex] (multiplying both sides by 3)
[tex] X =\frac{1}{4} [/tex]
So, Sally has [tex] \frac{1}{4} [/tex] pound of potatoes in her pantry.
