Случайный прохожий помог мне с пакетом.

Мне is the dative case of я (I).

• я – nominative (subject): Я иду. – I am going.
• меня – accusative/genitive (direct object, some prepositions): Он видит меня. – He sees me.
• мне – dative (indirect object, “to/for me”): Он помогает мне. – He helps me.

The verb помогать / помочь (to help) in Russian takes the person you help in the dative case:

• помог мне – helped me (literally: helped to me).

Both come from the verb помогать / помочь (to help), but they differ in aspect and meaning.

• помог – past tense, masculine, perfective (from помочь)

  • Focuses on the result, a completed single action.
  • He helped me (and the help is done, finished).

• помогал – past tense, masculine, imperfective (from помогать)

  • Focuses on process / repeated / habitual action.
  • He was helping me / used to help me / helped me repeatedly.

In this sentence, we talk about one completed act of help, so помог is natural.

In Russian, the default order is: adjective → noun.

So:

• случайный (adjective) + прохожий (noun)

Reversing them (прохожий случайный) would sound very odd and unnatural in modern Russian (except in poetry or for some special stylistic effect).

Also, случайный agrees with прохожий:

• masculine
• singular
• nominative case

So the pair случайный прохожий works as a unit: a random passer‑by.

No. Случайный literally means random / by chance / accidental.

In this context:

• случайный прохожий = a passer‑by who just happened to be there, someone I didn’t know, who was just passing by.

It does not imply the person is strange or weird, just that the meeting was by chance and the person is not previously known to the speaker.

Some common meanings of случайный:

• случайный человек – a person not connected to the situation, a random person
• случайная встреча – a chance meeting

Прохожий means “passer‑by”, literally “someone who is passing by”.

• It is a masculine noun (ending in -ий).
• The basic form (dictionary form) is прохожий – nominative, masculine singular.

For a specifically female passer‑by, you can say:

• прохожая – feminine form

Example:

• Случайная прохожая помогла мне с пакетом. – A random (female) passer‑by helped me with the bag.

Пакетом is the instrumental case of пакет.

The preposition с (with) in the sense of “together with / accompanying” normally uses the instrumental case:

• с кем? с чем? – with whom? with what?

So:

• пакет (nominative) → пакетом (instrumental)
• с пакетом – with the bag / package

The instrumental ending -ом is typical for masculine nouns like пакет:

• пакет – пакетом
• стол – столом
• билет – билетом

Пакет is a regular masculine noun. Singular forms:

• Nominative: пакет – the bag / package (subject)
• Genitive: пакета – of the bag
• Dative: пакету – to the bag
• Accusative: пакет – (same as nominative for inanimate nouns)
• Instrumental: пакетом – with the bag
• Prepositional: (о) пакете – about / in the bag

In the sentence, с пакетом uses the instrumental: with the bag.

Yes, that is correct and quite natural.

• Случайный прохожий помог мне с пакетом.
  • neutral order; just states what happened
• Мне помог случайный прохожий.
  • puts more emphasis on мне (someone helped me),
  • and often also emphasizes who it was (it turned out to be a random passer‑by).

Russian word order is relatively flexible; the cases show who does what. Changing the order usually changes emphasis, not basic meaning.

You must change both the noun and the verb to the feminine form:

• Masculine: Случайный прохожий помог мне с пакетом.
• Feminine: Случайная прохожая помогла мне с пакетом.

Changes:

• случайный → случайная (feminine adjective)
• прохожий → прохожая (feminine noun)
• помог → помогла (past tense feminine form of помочь)

Мне and с пакетом stay the same.

Past tense forms in Russian are built from the past tense stem plus a gender/number ending.

For помочь (perfective):

• masculine: помог
• feminine: помогла
• neuter: помогло
• plural: помогли

So the masculine form just ends in the consonant -г: помог.

For the imperfective помогать:

• masculine: помогал
• feminine: помогала
• neuter: помогало
• plural: помогали

That’s why the imperfective masculine has -л (помогал), but the perfective masculine помог does not: it’s a different verb form.

Approximate pronunciation with stressed syllables in CAPS:

• слуЧАЙный – slu-CHÁY-nyy
• проХОжий – pro-KHÓ-zhee
• поМОг – pa-MÓG (often pronounced [pamÓk] in fast speech)
• мне – mnye
• с – s
• пакЕтом – pa-KÉ-tam

Together (slowly):

• slu-CHÁY-nyy pro-KHÓ-zhee pa-MÓG mnye s pa-KÉ-tam

Stress pattern:

• случа́йный прохóжий помóг мне с пакéтом.