A slab of steel is pulled from a furnace at 540. After 27 minutes it has cooled to 296. The room is well ventilated and is kept at a steady temperature of 56. How long will it take for the steel to reach 239? Give your answer as a decimal number accurate to 2 decimal places.

Note: Such a situation falls under Newton's law of cooling, which states that the temperatureat timeobeys the differential equationwhereis some constant. You need to find the general solution of this DE and then use the information provided.

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