Question

The temperature at 12 noon was the temperature at 12 noon above zero if it decreases at the rate of 4 degree Celsius per hour until midnight

Answer 1

Answer:

Every hour temperature decrease by 2\degree C2°C

Therefore the temperature decrease 2\degree C2°C = 1 hour

So the temperature decrease 1\degree C1°C = \frac{1}{2}\ hour

2

1

hour

So the temperature at 18\degree C18°C = \frac{1}{2}\times18\ \ =\ 9\ hours\

2

1

×18 = 9 hours

Total time = 12 hours + 9 hours

= 21 hours

= 9 pm

thus, at 9pm the temperature would be 8\degree C\ below\ 0\degree C8°C below 0°C

Answer 2

Answer:

The temperature at 12 noon = 10° C above zero

The temperature is decreasing at 2° C per hour

8° C below zero = – 8° C

So, total fall in temperature from 10° C to 0° C and from 0° C to – 8° C = 18° C

Since the temperature falls 2° C in every one hour.

Therefore, to decrease 18° C, time taken = 18/2 = 9 hours

Present time is 12 noon so, the time when the temperature is – 8° C= 12 noon + 9 hours

So, The time at which the temperature will be – 8° C = 9 PM

At 9 PM, the temperature is – 8° C, the temperature at 12 midnight will be =

(- 8° C) + (- 2° C × 3 hours)

= (- 8° C) + (- 6° C)

= – 14° C

So, at 12 midnight the temperature will be – 14° C.