(10) The temperature of a rod was 10°C above zero. It was kept in a freezer at 2 p.m. If its temperature
decreased at the rate of 3°C per minute, at what time would the temperature be 8°C below zero? And
what would be the temperature at 2:15 p.m.?
Answers
Answer:
Happy Raksha bandhan
The temperature of rod was 10 degrees celsius above 0 means = 0 + 10 = 10degrees celsius.
Rate of temperature decreasing - 3 degrees celsius / per minute [ 1 degree celsius / 20 secs ]
Time it was kept in freezer - 2 p.m.
Time the temperature will decrease to 8 degrees celsisus.
Foe every minute the temperature will decease 3 degrees celsius , here it only decreased to 8 degrees celsius , decreased 2 degrees celsius ;
That means it has been less than a minute ;
So , it has been decreased 2 degrees celsius [ Rate of decreasing - 1 degree celsius / 20 secs ]
So , it has been 2x 20 secs = 40 secs. That means , The time would be exactly 2 : 00 : 40 PM
Temperature for the time 2:15 PM ; 15 minutes done after placing it in the freezer ; [ Rate of decreasing 3 degrees celsius / per minute ]
15 minutes done = 15 min x 3 = 45 degrees celsius increased ; Means 10 degrees celsius - 45 degrees celsius = -35 degrees celsius.
Therefore the temperature of the rod was -35 degrees at the time of 2:15PM .