Question

The temperature is 45F. The temperature will decrease by 2F each hour. Let h be the number of hours. When will the temperature be below 2 f

Answer 1

23rd hours

Explanation:

This is problem based on arithmetic progression in which our first term is 45 , and the common difference is -2

we have to find the n when the nth term is 2.

The formula for nth term of an AP is

`a_(n)=a+(n-1)d`

replacing the values in the formula

`a_(n)=a+(n-1)d\\2=45+(n-1)(-2)\\2=45-2(n-1)\\-43=-2(n-1)\\21.5 = n-1\\n=22.5\\`

hence at 22.5 hours it will reach 2F or we can say that after 23 hours the temperature will be below 2F