Verbs and Tense

Sita went to school. Manav writes "Sita school gaya" (using the masculine form), thinking the past-tense verb always stays the same. His teacher says the verb here matches the subject's gender. Who is right?

Meeta says "voh padhti hai" (she reads/studies) and "usne padha" (she read/studied) refer to the same time period, just with different words. Her brother says the two show different tenses. Who is right?

Ram ate food. Kabir writes "Ram khaana khaya" (dropping "ne"), thinking it is not necessary. His sister says the sentence is incomplete without "ne" here. Who is right?

Ram (masculine) read the book (feminine, "kitaab"). Arjun writes "Ram ne kitaab padha" (masculine verb form), thinking the verb always matches the subject Ram's gender. His sister says the verb here matches "kitaab", not Ram. Who is right?