Answer:
205
Explanation:
Given
N(t) = 100 + 15t is the equation of the relation.
We're asked to find N(7)
Taking a look at the question again and putting it side by side the equation
N(t)
N(7)
We can deduce that t = 7, and as such, solve for it in the equation given
N(7) = 100 + 15(7)
N(7) = 100 + 105
N(7) = 205
Therefore, the number of unread mails after 7 days will be 205