Can you do number 7 and explain to me how you got the answer?
1 answer:
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Answer:
(1) The required ratio of spirit to varnish is 1:3.
(2) You need 80 ml of mineral spirit.
(3) The ratio of tapestries' heights to width is 3:2.
Step-by-step explanation:
(1) If you need to mix 25% mineral spirit to the varnish, then the solution would contain 25% mineral spirit and 75% varnish.
So,
Thus, The required ratio of spirit to varnish is 1:3.
(2) If you use 240ml of varnish, then this quantity is 75% of the total solution or ration of varnish to the total solution will be 3:4.
Let be the quantity of total solution.
Then, .
⇒
⇒
⇒
⇒
That is, total solution is 320 ml.
Now, Spirit = Total solution - Varnish
⇒Spirit = 320ml-240ml
⇒Spirit = 80ml
Hence, if you use 240 ml of varnish, you need 80 ml of mineral spirit.
(3) Robison's tapestries all measure 1.5m long and 1m wide. First, we express dimensions in whole numbers by multiplying them by 10.
Then, dimensions are 15m long and 10m wide.
Now, Height : Width = 15:10
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Hence, the ratio of tapestries' heights to width is 3:2.
Answer:
The 98% confidence interval for the mean usage in the March quarter of 2006, in kWh, was (333.87, 416.13).
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 30 - 1 = 29
98% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 29 degrees of freedom(y-axis) and a confidence level of . So we have T = 2.462
The margin of error is:
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 375 - 41.13 = 333.87 kWh
The upper end of the interval is the sample mean added to M. So it is 375 + 41.13 = 416.13 kWh
The 98% confidence interval for the mean usage in the March quarter of 2006, in kWh, was (333.87, 416.13).