Using “would” with the present tense in conditional clauses

Preamble

The passage you cite has various verb form inconsistencies and the ungrammatical use of 'the' in the phase 'enter the university next year'. You state that the passage comes from a tutorial text. Perhaps you could give a little more information about both the passage and the tutorial text, together with the task that is based on them.

Analysis

That aside, the main issue here is how to construct conditional sentences. This is a tricky issue for non-native English learners, and many pedagogic grammars try to simplify it by reducing the possibilities to three - which they call the First, Second and Third Conditionals. Certainly, these are three common patterns, but I would be very wary of any grammar rules 'prescribing' the use of the present tense in the if-clause (protasis) when using 'will + infinitive' in the main clause (apodosis) - or vice versa.

As Michael Lewis points out in the section on Conditional Sentences in The English Verb: An Exploration of Structure and Meaning (p148):

It is the verb phrase not the sentence which is the fundamental unit requiring analysis. Certain combinations are, for semantic reasons, highly frequent, while others are less frequent or even impossible. ...

A particular misunderstanding frequently arises in the teaching of so-called conditional sentences. It is common to teach three basic kinds. ...

[Lewis gives examples]

If students are taught only the first, second and third conditionals, they will know only a small, admittedly highly frequent, sub-set of the possibilities. It is not necessary to teach the fourth conditional, the fifth conditional, etc., but it is important to recognise that the possibility arises from the meaning of the individual clauses ... . The explanation of the use of a form in a conditional sentence is exactly the same as that of its occurrence in any other utterance.

The underlying principle behind this is that each main verb phrase is treated independently.

Applying this explanation to your example sentence, the speaker is probably using 'would' (He would be able to pass all the exams) rather than 'will' (He will be able to pass all the exams) to express doubt that 'he' has thought it over and is going to pass the exams.

As to the second clause, 'studied' is the more likely form in this context, and would conform to the common Conditional 2 pattern. But perhaps the speaker is expressing the simple fact that exam success is assured if studying is done at full speed.

Examples of 'mixed conditionals'

Mixing the so-called first and second conditionals in this way is not uncommon. Below are several authentic examples from Google. That said, if you are studying for English exams, you are probably better advised to stick to the 'prescribed' patterns.

Walter hopes that if we can become rich, he would be able to provide a better life for his family.

If God is omnipotent, he would be able to prevent all of the evil.

If I am fortunate enough to be selected for a grant, I would be able to pay for child care.

If your portfolio manages to offer an annual return of 12 per cent, you would be able to create a corpus of Rs 1 crore in 25.5 years.

If this is the case, you would be able to claim the new 20pc tax credit.

If all goes to plan, you would be able to be play an emulated NES game within an emulated GameCube game.

If you follow the 4% rule, you would be able to withdraw at least $40,000 a year during retirement.

You would be able to get 82.5 servings of beer if each serving is 12 ounce.