If a girl cuts the grass in 3 hours and a boy cuts it in 2 hours what would be the time if they cut it toghther.?
2 answers:
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Answer:
The number of once is 9.1
The number of hundreds is 8.9
Step-by-step explanation:
Given as :
The total of digits having ones and hundreds = 900
The sum of digits = 18
Let The number of ones digit = O
And The number of hundreds digit = H
So, According to question
H + O = 18 .........1
100 × H + 1 × O = 900 ........2
Solving the equation
( 100 × H - H ) + ( O - O ) = 900 - 18
Or, 99 H + 0 = 882
Or , 99 H = 882
∴ H =
I.e H = 8.9
Put the value of H in eq 1
So, O = 18 - H
I.e O = 18 - 8.9
∴ O = 9.1
So, number of once = 9.1
number of hundreds = 8.9
Hence The number of once is 9.1 and The number of hundreds is 8.9
Answer
If inspection department wants to estimate the mean amount with 95% confidence level with standard deviation 0.05 then it needed a sample size of 97.
Given 95% confidence level, standard deviation=0.05.
We know that margin of error is the range of values below and above the sample statistic in a confidence interval.
We assume that the values follow normal distribution. Normal distribution is a probability that is symmetric about the mean showing the data near the mean are more frequent in occurence than data far from mean.
We know that margin of error for a confidence interval is given by:
Me=
α=1-0.95=0.05
α/2=0.025
z with α/2=1.96 (using normal distribution table)
Solving for n using formula of margin of error.
n=
=96.4
By rounding off we will get 97.
Hence the sample size required will be 97.
Learn more about standard deviation at brainly.com/question/475676
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The given question is incomplete and the full question is as under:
If the inspection division of a county weights and measures department wants to estimate the mean amount of soft drink fill in 2 liters bottles to within (0.01 liter with 95% confidence and also assumes that standard deviation is 0.05 liter. What is the sample size needed?