Answer:
≥ 420 boards
Step-by-step explanation:
Write the required relation between cost per board and "x" (the number of boards that must be sold).
143 + 30240/x ≤ 215 . . . . . . . note that the first term is <em>not</em> 143x
Subtract 143
30240/x ≤ 72
Multiply by x/72. This is a positive number because x is a positive number.
30240/72 ≤ x
420 ≤ x
At least 420 surfboards must be sold to limit the final cost per board to $215.
Answer: x - 6 = 15
Step-by-step explanation:
Answer:
In an experiment of flipping two coins, there are four possible outcomes.
Step-by-step explanation:
Answer:
Step-by-step explanation:
A) From the stem-leaf plot, we see that out of 21 tunas, 5 have dangerous levels of copper since the levels go beyond 5.7 parts per million. The required proportion is 5/21=0.2381
B) Given the sample mean is {x}=4.77, sample standard deviation s=1.16 and the sample size is n=21.
Since the population standard deviation is not known, we use t-distribution.
So the 98% CI for mean is
4.77 ± t{1-0.02 /2,20} x 1.16/sqrt(21) = (4.13, 5.41)}
We are sure with 98% confidence the true copper level (in parts per million) lies in the interval (4.13, 5.41)