Conjunction (MGMAT verbal)

[PranabA704]

Could you please help me out, as I have some issue with conjunction-

for example the two sentences taken from the MGMAT verbal lesson -2

My professor is intelligent; I've learned a lot from her

My professor is intelligent and I've learned a lot from her.

Please correct me, as I can understand the sentence with conjunction is preferred but is it also true that the two independent clause should be closely related when we use semicolon, and it is not necessary in case of conjunction-

For example-

John walked to school; he later skipped his class.(both independent clause are closely related)

John walked to school and Earl drove to theater.(both clauses are not related) and it will be wrong if we replace 'and' by semicolon -John walked to school; Earl drove to theater.

Further more the following sentence (MGMAT sentence correction pg 39)

The teacher is confident that her students mastered the lessons.

Can we also put it as- The teacher is confident and her students mastered the lessons. or The teacher is confident; Her students mastered the lessons.
is it always necessary to have independent clause after semicolon or is there any exception.
Please let me know if my reasoning is correct.

[RonPurewal]

hi,
this folder is for questions from the MPrep practice tests only. there's another folder for questions about items from other MPrep materials.

please post your questions in the correct place. thank you.