Question

1. The temperature at 12 noon was 10°C above zero. If it decreases at the rate of 2°C
per hour until midnight, at what time would the temperature be 8°C below zero?
What would be the temperature at mid-night?​

Answer 1

This can be taken as an AP

Where first term = 10
And last term = -8
Common difference = -2

We have to find number of terms

last term = first + n(common difference -1)

-8= 10 +n(-3)
-18/-3 = n

N=6

Therefore after 6hrs it will be -8

Therefore at 6:00 clock it will be -8C

At midnight n = 12

Last term = first + n(common diff - 1)
Last term = 10 + 12(-3)
Last term = 10-36


Therefore are 12:00 in the night it will be -26C