Answer:
36 runners finished the race.
Step-by-step explanation:
In the first half of the race, 1/4 of them dropped, so we need to calculate 1/4 of 80:
(1/4) * 80 = 80/4 = 20
If 20 runners dropped out, now we have 80 - 20 = 60 runners.
Then, in the second half, 2/5 of the remaining runners dropped out, so:
(2/5) * 60 = 2*60/5 = 120/5 = 24
If 24 runners dropped out, now we have 60 - 24 = 36 runners.
So, 36 runners finished the race.
Fun fact
if f(a)=b then f⁻¹(b)=a
so
if f⁻¹(b)=a then f(a)=b
so we find f(x)=27 and the solve for x
f(x)=3x=27
3x=27
divide both sides by 3
x=9
so if f(9)=27 then f⁻¹(27)=9
problem solved
answer is 9
Answer:
11
Step-by-step explanation:
Step-by-step explanation:
Confidence interval = mean ± margin of error
CI = μ ± ME
The mean is μ = 8.7.
Margin of error = critical value × standard error
ME = CV × SE
At 95% confidence and 9 degrees of freedom, CV = 2.262.
SE = s / √n
SE = 3.3 / √10
SE = 1.04
The margin of error is:
ME = 2.262 × 1.04
ME = 2.36
CI = 8.7 ± 2.36
CI = (6.34, 11.06)
