Question

The temperature at 12 noon was 10o

C above zero. If it decreases at the rate of 2oC per

hour until midnight, at what time would the temperature be 8oC below zero? What would

be the temperature at midnight?
I will mark you as brainly

Answer 1

 Difference in temperatures = 10 – ( -8) = 10 + 8 = 18
Time taken for reduction of 8°C = 8÷2 = 4 hours
At 4 PM the temperature would be 8°C below zero.
From 12 noon to midnight, 12 hours elapse
Hence, reduction in temperature = 12 x ( -2) = - 24
Hence, temperature at midnight = 10 - 24 = - 14°C

Answer 2

Solution : Temperature at 12 Noon = 10°C above 0°C = 10°C

              It decreases at 2° per hour.

Final temperature = 8°C below 0 = -8°C

Change in temperature = 10 - ( -8 ) = 18°C.

Rate of decrease = 2° per hour.

Time = 18 / 2 = 9 hours.

So, Time at which temperature would be 8°C below zero = 12:00 + 9:00 = 21:00

                  So, the time at which temperature goes 8°C below 0 is 9:00 PM.

Also, The temperature at 12 :00 PM = 10° C, As temperature decreases at 2°C,

Temperature at mid night = 10° C - 2 ( 12 ) = 10 - 24 = -14° C.