9. There are 40 minutes to solve a test of 60 questions. A student completes 20 questions in 20 minutes
He continues with the same speed and leaves the hall 10 minutes earlier. The number of questions solved by him?
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Respuesta :

He solved 30 questions.
He solved one question in one minute.
This if he continued at the speed and there are 40 minutes to solve the test and he leaves 10 minutes earlier. He is left with 30 minutes and one minutes per question . Therefore, he solved 30 question.