The correct option is "d".
Given that L = 0.8T²
length of pendulum = 30ft
L= 0.8T²
30 = 0.8T²
T² = 30 / 0.8
T² = 37.5
T = √37.5 = 6.1 seconds
<span>So, 6.1 is the closest to the period in seconds for a pendulum that is 30 ft long.</span>
The answer is 2/8 and 4/12 because if you times the 1/4 equation by 2 you would get 2/8 and then times 1/4 by 3 then you would get 4/12
Answer:

Step-by-step explanation:
Let:

We need to eliminate one of the variables, so let's use elimination method. First multiply (1) by 2

Now subtract (2) from 2*(1) in order to eliminate x:

Solving for y:
Multiplying both sides by -1

Finally, replacing the value of y in (1)

Solving for x:
add 41 to both sides:

Multiply both sides by 1/2:

The order you apply the adjustments does make a difference because the percents that are applied will be applied to different amount.
For example, 80% of 100 = $80. The price would be $180.
Decreasing this by 25% 25% of 180 = $45; 180-45 = $135.
25% of 100 is not the same as 25% of 180.