Urgent help plz

[tubby]

You are given a graph simlar to this
(drew it the best i could)

and this formula that you work out
T=7e^(-kt) + 4
T= temp
t= time
k= constant

then the qn asks you find value of T when t = 12
dilemma is your not supposed to know k

in later qns you work it out but this is qn 1 c
and you work out k in like qn 2 - 3

the value of T should be slightly higher then 4 but i dont know how i should express the answer!
plz help urgen response would be nice thnk you

 

[tkhunny]

T=7e^(-kt) + 4
T= temp
t= time
k= constant
then the qn asks you find value of T when t = 12

The order of the questions you will have to take up with the author.

As far as expressing the value for t=12, just do it.

T(12) = 7*e^(-12*k) + 4

That's about it, in the absense of 'k'.

If k = 1, T(12) = 4.000043009 <== That's just a hair greater than 4, as you surmised.