Final answer:
The engineer should have counted 12 trucks.
Step-by-step explanation:
To find the number of trucks the engineer should have counted, we can solve the given equation:
2/7 = t/(54-t)
Multiplying both sides of the equation by (54 - t) gives us:
(2/7)(54 - t) = t
Expanding the equation:
108/7 - (2/7)t = t
Adding (2/7)t to both sides:
108/7 = (9/7)t
Multiplying both sides by 7/9:
12 = t
Therefore, the engineer should have counted 12 trucks.