please help me to solve

Question

You have 59 minutes to take an exam of 20 questions. After you finish the first 10 questions, you realize you must answer the remaining questions twice as fast to finish the exam. How many questions per minute were you answering?

Answer 1

you were doing ten questions in 40 minutes, and ten questions remain to be done in 20 (approx.) minutes, so the new rate would have to be 2 min. per question.

 

Forgive me for upping the allotted time to 60 minutes...you get the general idea, I trust.