Answer:
5m/8
Explanation:
Function T gives the time the Hobbits have to prepare for the attack, T(k), in minutes, as a function of troll's distance, k, in meters.
Function V gives visibility from the watchtower, V(m), in meters, as a function of the height of the watchtower, m, in meters.
Therefore, T(V(m)) will give the time the Hobbits have to prepare for the troll attack as a function of the height, m, of the watchtower.
We can input m into function V to obtain the visibility from watchtower, V(m), in meters. Since visibility indicates the distance you can see, this also gives the distance of the trolls. This can then be input into function T to obtain the time that the Hobbits have to prepare for a troll attack.
Let's find T(V(m)) by substituting the formula for V(m) into function T as shown below.
T(V(M))=T(50m)
=50m/80
We can simplify this as follows:
=50m/80
=5m/8