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.
Answer:
the answer is 1 2/3 - 1 3/7 ÷ (1/2+ 4/7) = 2/9
This year
2:7
18:?
well 2*9=18
so 7*9=63
18/63
(18+63=total 81 students)
Last year
1/8
multiply by 9
9/72
9 less students this year
You mean a square has an AREA of 100 square meters?
The length of 1 side equals square root of 100 = 10 meters.
Therefore perimeter = 4 * 10 = 40 meters.