Is this triangle not similar because it only has two proportional sides?

The triangles are similar.

Step-by-step explanation:

They share a common angle (∠S) and the ratio of the two sides is the same, i.e. SP/SQ = SR/ST

25

Step-by-step explanation:

To find the answer, we want to figure out how many times 1/3 goes into 8 1/3, so we use division.

convert 8 1/3 into an improper fraction

8 1/3 = (3 * 8 + 1)/3 = 25/3

we use 25/3 for the numerator and 1/3 for the denominator

so the number of hamburgers she can make is

(25/3) / (1/3)

= (25 / 3) * 3 the 3's cancel out

= 25 hamburgers