"How did your life change if you have as much money as Bill Gates?" Is this sentence correct?

I am a teacher of English in Japan. I happened to see a weird sentence from a notebook of my student. It says,

"How did your life change if you have as much money as Bill Gates?"

And my fellow teacher approved this sentence.

But I think I should say like,

"How would your life change if you had as much money as Bill Gates?"

Is the sentence on the title correct? I need your opinion please.

Solution 1:

There are two issues: Tense agreement and construction of a conditional.

The first sentence is not correct because there is not tense agreement between the verbs “did...change” (past tense) and “have” (present).

A second reason is that the construction “How...if...” calls for a conditional, so “would” is a better auxiliary than “did.” Conditional Verbs

Conditional verbs can be used in the past, present, or future tense, and auxiliary verbs like can/could, will/would, and may/might are important in forming conditionals.

So even with tense agreement “How did your life change if you had as much money as Gates?” would still not be perfect.

The sentence you propose, "How would your life change if you had as much money as Bill Gates?" is perfect.

Solution 2:

English is remarkably plastic. One can wrench many seemingly ungrammatical statements into line by providing suitable context or by specifying an unusual point of view.

In your fellow-teacher’s example, we could posit this hypothetical context:

• he (or any pronoun you prefer) is as rich as Bill Gates, and has been for a long time;
• he experienced a significant change, such as becoming a lot more calm or frantic, or generous or miserly, or perhaps found faith, etc;
• the speaker is amazed at the change, thinking that such a change is unheard of in a man of wealth.

The speaker then expresses that amazement by asking the question your fellow-teacher approved. The change is in the past, and the wealth is in the ‘timeless’ or ‘continuing’ present, so the question correctly expresses the speaker’s intent.

With that same context, your alternative wouldn’t express the speaker’s intent.

However, because there is some conceivable context for each question that validates that question, both questions are grammatical.

Instead of asking whether the bare question of whether a sentence is correct, it might be more useful to have the student or teacher express the context (using any convenient language), and then ask whether the English sentence fits that context.