1.75 is the answer. Hope this helps.
Answer:
A. 49 + 16 (t - 1)
Step-by-step explanation:
Plug in t = 1 to test for the first hour:

Test as many values as you like, but testing t = 5:

You can see that plugging in just a few values confirms the answer.
x² + 10x = 26
x² + 10x + 25 = 26 + 25
x² + 5x + 5x + 25 = 51
x(x) + x(5) + 5(x) + 5(5) = 51
x(x + 5) + 5(x + 5) = 51
(x + 5)(x + 5) = 51
(x + 5)² = 51
x + 5 = ±√(51)
- 5 - 5
x = -5 ± √(51)
x = -5 + √(51) or x = -5 - √(51)