Viginti pueri ac puellae post scholam ad hortum venerunt, et magistra viginti quaestiones eis proposuit.

No. Viginti is a cardinal number, and numbers like viginti are normally indeclinable in Latin. That means they do not change form for gender, number, or case.

So you get:

• viginti pueri = twenty boys
• viginti puellae = twenty girls
• viginti quaestiones = twenty questions

Unlike an adjective such as bonus, bona, bonum, viginti does not match the noun in form.

Normally it means twenty children total, made up of boys and girls.

In other words, viginti is understood with the whole group: boys and girls = twenty altogether.

If Latin wanted to make it clear that there were twenty boys and twenty girls, it would usually say the number twice, such as:

• viginti pueri et viginti puellae

So in your sentence, the most natural reading is a mixed group of twenty boys and girls.

Yes. Ac and et both mean and.

In this sentence, ac links pueri and puellae:

• pueri ac puellae = boys and girls

A few useful points:

• ac is a shortened form of atque
• ac/atque often has a slightly closer or smoother linking feel than et, though in many sentences the difference is small
• Latin writers often vary between them for style

So here you can simply understand ac as and.

Because post is a preposition that takes the accusative case.

So:

• schola = nominative or ablative singular
• scholam = accusative singular

After post, Latin uses the accusative:

• post scholam = after school

This is something you largely just have to learn with the preposition: post + accusative.

Yes, in isolation post scholam could theoretically mean either:

• after school in a time sense
• behind the school in a place sense

Latin post can be used both temporally and spatially.

But in this sentence, the context makes after school the natural meaning:

• post scholam ad hortum venerunt = they came to the garden after school

That sequence of events strongly points to time, not location.

Because ad with the accusative usually expresses motion toward a place:

• ad hortum venerunt = they came to the garden

By contrast:

• in horto = in the garden or inside the garden, describing location rather than movement toward it

So the difference is:

• ad hortum = to the garden
• in horto = in the garden

Since the sentence is about arriving somewhere, ad hortum is the right choice.

Venerunt is the perfect tense of venire, meaning to come.

The Latin perfect often corresponds to the English simple past:

• venerunt = they came

Depending on context, it can also sometimes feel like they have come, but in a narrative sentence like this, they came is the most natural translation.

Also, the ending -erunt shows that the verb is:

• third person plural
• perfect tense

So venerunt means they came.

Latin has no articles. There is no direct equivalent of English the or a/an.

So magistra can mean:

• the teacher
• a teacher

You decide from context which is more natural. In this sentence, the teacher is the most likely translation.

This is very common in Latin: nouns often appear without any word corresponding to an English article.

Eis is dative plural of the pronoun is, ea, id, and here it means to them.

It refers back to the boys and girls.

So:

• magistra viginti quaestiones eis proposuit
• the teacher put twenty questions to them

A useful thing to remember is that eis is often the form you will see for to them or for them.

Because proponere can mean to put forward, to propose, or in this context to ask/set before someone.

Its construction here is:

• viginti quaestiones = direct object, what the teacher posed
• eis = indirect object in the dative, to whom she posed them

So literally it is something like:

• the teacher set twenty questions before them

That is why you see both:

• quaestiones in the accusative
• eis in the dative

Because quaestiones is the direct object of proposuit.

The teacher did the action of posing, and the thing posed was twenty questions.

So:

• quaestio = question
• quaestiones = questions
• here it is accusative plural, because it is the object of the verb

This is a very common Latin pattern: the thing directly affected by the verb goes into the accusative.

Because Latin word order is much more flexible than English word order.

Latin often puts the verb at or near the end of the clause, especially in straightforward narrative prose:

• ... ad hortum venerunt
• ... eis proposuit

This does not mean the verb must always come last. Latin can move words around for emphasis, rhythm, or style. The endings usually tell you what each word is doing, so word order is less rigid than in English.

In this sentence, the ending position of the verbs is very natural and typical.

We know from both form and sense.

First, magistra is in the nominative singular, which is the normal case for the subject.

Second, proposuit is third person singular, so it needs a singular subject:

• magistra ... proposuit = the teacher posed

Meanwhile:

• quaestiones is accusative plural, so it is the direct object
• eis is dative plural, so it is the indirect object

So the grammar clearly shows that magistra is the subject.

Because Latin verb endings already tell you the person and number.

For example:

• venerunt already means they came
• proposuit already means she/he/it posed

Latin therefore often leaves out subject pronouns unless they are needed for emphasis or contrast.

So instead of saying an extra word for they or she, Latin usually lets the verb ending do that job.