Question

The temperature at 12 noon was 16℃ above zero. If it decreases at the rate of 2℃ per hour until midnight . then (i) at what time would the temperature be 10℃ below zero ? (ii) What would be the temperature at midnight ?​

Answer 1

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.

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