Joan is given 1 x 60 = <<1*60=60>>60 minutes to answer the English exam.
So Joan will spend 60/30 = <<60/30=2>>2 minutes for each English question.
She is given 1.5 x 60 = <<1.5*60=90>>90 minutes to answer the Math exam.
So, she will spend 90/15 = <<90/15=6>>6 minutes for each Math question.
Hence, Joan has 6 - 2 = <<6-2=4>>4 minutes more for answering each question in Math than in English.
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