"You eat a sandwich."
अनुवाद:तुम एक सैंडविच खाते हो।
Yes that is correct and तुम एक सैंडविच खाओ is another correct answer here. Notice though that it is खाओ and not खाऔ. This sentence in fact has 21 different correct answers - covering all forms of you, all genders, optionally using एक and considering the sentences as both a present tense sentence and a command.