Ex.1.4

Q.5  The temperature at 12 noon was 10ºC above zero. If decreases at the rate of 2ºC/hr untill midnight ,at what time would the temperature be 8ºC below 0? What would be temperature at midnight? 

Temperature at 12 noon was 10^o C

Initial temperature = 10^o C

Final temperature = -8^o C

Total decrease = Final temperature - Initial temperature = -8^o C - 10^o C = -18^o C

Temperature decrease by 2^o C in every 1 hour

Time required to reach -18^o C = 18/2 = 9 hours

Hence, the temperature at 9 pm would be -8^o C