but when the questions are "you need 4 networks which subnet mask would you use on this ip: 10.1.1.25"
That's gibberish. There's no way to know based on what is stated.
I probably missed the actual question.. but questions similar to that confuse me.
It's all math and high school style word problems. It's all about "to meet the requirements", what options would you choose so that the sizes are correct.