##### The temperature at 12 noon was 10oC above zero. If it decreases at the rate of 2oC per houruntil mid-night, at what time would the temperature be 8oC below zero? What would be the temperature at mid-night?

It is given in the question that,

Temperature at 12 noon = 10oC

Also,

Change in temperature per hour = - 2oC

Therefore,

Temperature at 1:00 PM = 10oC + (-2oC) = 8oC

Temperature at 2:00 PM = 8oC + (-2oC) = 6oC

Temperature at 3:00 PM = 6oC + (-2oC) = 4oC

Temperature at 4:00 PM = 4oC + (-2oC) = 2oC

Temperature at 5:00 PM = 2oC + (-2oC) = 0oC

Temperature at 6:00 PM = 0oC + (-2oC) = - 2oC

Temperature at 7:00 PM = - 2oC + (-2oC) = - 4oC

Temperature at 8:00 PM = - 4oC + (-2oC) = - 6oC

Temperature at 9:00 PM = - 6oC + (-2oC) = - 8oC

Hence,

The temperature will be 8oC below zero at 9:00 PM

Now,

Change in temperature in 12 hours = - 2oC × 12

= - 24oC

Also,

At midnight the temperature will be = 10 + (-24)

= - 14oC

Hence,

The temperature at midnight will be 14oC below zero

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