How many punctuation errors are found in a sentences belowhave you ever run in a relay race. if you imagine a relay race, then you'll understand how the pony express worked.

Salutations!

There are 3 grammatical errors. The first sentence: have you ever run in a relay race.

When you start a sentence, you need to start it with a capital letter. This sentence is asking a question, so you need to add a question mark.

Have you ever run in a relay race? (Rewritten accurately)

The second sentence: if you imagine a relay race, then you'll understand how the Pony Express worked.

after a full stop or period, you need to always start the sentence with a capital letter.

If you imagine a relay race, then you'll understand how the Pony Express worked. (rewritten accurately)

Hope I helped (:

Have a great day!