Does 25/60 and 8/20 form a proportion ?

No.

Step-by-step explanation:

Change it so that both fractions would have the same denominator. Note that what you do to the denominator, you must also do to the numerator.

Multiply 3 to both the numerator & denominator of 8/20

(8/20)(3/3) = 24/60

24/60 ≠ 25/60 ∴ these 2 fractions are not proportional.

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question: how many people can she serve?

answer: she can serve 16.66666667 people. so she can only give 16 people a complete serving.

question: does she have enough ice cream for her guests?

answer: no. explanation: she only has enough for 16 people to have a full serving. however, she can give a 17th person a partial serving.