Agree. I think it should be 我看了书两个小时二十五分钟

It's not wrong per se, but this form stresses something a little different than "I read a book for 2 hours and fifteen minutes." It's more like, "I spent 2 hours and fifteen minutes of my day reading." I wonder who designed this program.

This doesn't look right.

can someone explain this ‘的’?

This is not right - should be 我两个小时十五分钟读书。

我读了两小时十五分钟的书 Is the google's translate, looks similar.

Good lord, these exercises are all kinds of inconsistent about word order.

我两个小时五点分钟看书 or 我两个小时五点分钟看了书 if "read" is past tense?

What's wrong with:

我两个小时十五分钟看了书

It follows the word order of: subject + time + verb + object, but it's marked as wrong

that is such a weird sentence structure... -∆-;;

I don't understand the syntax of this sentence at all. Why is 的 used to link 书 to the length of time reading took place